
Class _A£ 

Book n 

Copyright^ . 



COPYRIGHT DEPOSIT 



FRONTISPIECE 



Normal Fundus of a Dog's Left Eye. 



OPHTHALMOLOGY 

for 

VETERINARIANS 



BY 

WALTER N. SHARP, M.D. 

PROFESSOR OF OPHTHALMOLOGY IN THE INDIANA VETERINARY 

COLLEGE ; OPHTHALMIC SURGEON TO THE INDIANAPOLIS CITY 

HOSPITAL 



ILLUSTRATED 



PHILADELPHIA AND LONDON 

W. B. SAUNDERS COMPANY 

1913 



4 



<b 



6 



Copyright, 1913, by W. B. Saunders Company 



PRINTED IN AMERICA 



PRESS OF 

W. B. SAUNDERS COMPANY 

PHILADELPHIA 



©CI.A346118 



DEDICATED TO THE MEMORY OF MY SON 

WILFRED EMERSON SHARP 

WHO DEPARTED THIS LIFE 

SEPTEMBER 10, 1904 
IN HIS EIGHTEENTH YEAR 



Digitized by the Internet Archive 
in 2011 with funding from 
The Library of Congress 



http://www.archive.org/details/ophthalmologyfor01shar 



PREFACE 



This small volume is the fulfilment of a wish often 
expressed by the students of the Indiana Veterinary 
College. It comprises, with the exception of dissections 
and clinical demonstrations, the work with the senior 
class in this department during the term. 

As external diseases of the eye are principally seen 
in animals, more attention has been given such diseases 
in as plain and few words as is consistent with the sub- 
ject, so that they may be comprehended by the student 
as well as by the practitioner. 

I am indebted to Drs. G. H. Robberts, W. B. Craige, 
and other members of the Indiana Veterinary College 
for valuable assistance, and to Drs. G. E. deSchweinitz, 
Alexander Duane, Wm. C. Posey, and other authors of 
works on ophthalmology for valuable information. 

As the literature upon diseases of the eye in animals 
is extremely limited, I have been obliged to draw 
largely from "Law's Veterinary Medicine," especially 
on the subject of parasites of the eye. 

Walter N. Sharp. 

Indianapolis, Indiana, 
March, 19 13. 



CONTENTS 



CHAPTER I page 

Anatomy of the Eye 1 1 

Definition, n — Coats, 14 — The Eye Internally, 14 — The 
Sclera, 14 — The Chorioid, 15 — The Retina, 17 — The Cornea, 
20 — The Iris, 21 — The Pupils, 24 — The Ciliary Body, 24 — The 
Lens, 25 — The Vitreous, 26— The Conjunctiva, 27 — The 
Nictitans Membrane, 27. 

CHAPTER II 

Systematic Examination of the Eye 29 

The Lids, 29 — -The Conjunctiva, 30 — The Cornea, 30 — 
The Pupils, 30 — The Iris, 31 — The Lens, 31 — The Tension, 32. 

CHAPTER III 

Diseases of the Lids 33 

General Description of the Lids, ^3 — Edema, 35 — Emphy- 
sema, 35 — Ecchymosis, 35 — Burns, 35 — Wounds, 36 — Ectro- 
pion, 36 — Entropion, 36 — Lagophthalmus, 37 — Ptosis, 37 — 
Tarsitis, 37 — Elephantiasis, 37 — Blepharospasm, 38 — Ankylo- 
blepharon, 38 — Blepharitis Marginalis, 38 — Hordelum, or Stye, 
40 — Chalazion, 40 — Tumors of the Eyelids, 41 — Ulcers of the 
Lid, 42 — Abscess of the Lid, 42 — Trichiasis, 43 — Distichiasis, 44. 

CHAPTER IV 

Operations on the Lids 45 

Ectropion, 46 — Entropion, 51 — Trichiasis, 53 — Ankylo- 
blepharon, 55 — Ptosis, 56. 

CHAPTER V 

Diseases of the Lacrimal Apparatus 57 

Dacrocystitis, 57 — Stenosis of the Nasal Duct, 58. 

5 



6 CONTENTS 

CHAPTER VI 

PAGE 

Muscles of the Eyeball 59 

Affections of the Muscles, 61 — Ophthalmoplegia, 62. 

CHAPTER VII 

Diseases or the Conjunctiva 64 

Conjunctivitis, 64 — Acute Catarrhal Conjunctivitis, 64 — 
Chronic Conjunctivitis, 66 — Purulent Conjunctivitis, 68 — 
Phlyctenular Conjunctivitis, 71 — Trachoma, 72 — Follicular 
Conjunctivitis, 74 — Xerosis, 75 — Membranous Conjunctivitis, 
76 — Pinguecula, 78 — Tuberculosis of the Conjunctiva, 79 — 
Pterygium, 79 — Foreign Bodies in the Conjunctiva and 
Cornea, 80 — Burns of the Conjunctiva and Cornea, 83 — 
Tumors of the Conjunctiva, 84 — Inflammation of the Nicti- 
tans Membrane, 86. 

CHAPTER VIII 

Diseases of the Cornea 88 

Keratitis, 88 — Ulcers of the Cornea, 90 — Pannus,' 97 — 
Phlyctenular Keratitis, 99 — Herpes CorneEe, 99 — Dentritic 
Keratitis, 100 — Filamentous Keratitis, 100 — Desiccation 
Keratitis, 101 — Neuroparalytic Keratitis, 101 — Keratomala- 
cia, or Xerosis of the Cornea, 102 — Staphyloma of the Cornea, 
102 — Keratectasia, 105 — Keratoconus, or Conic Cornea, 105 — ■ 
Keratoglobus, 105 — Opacities of the Cornea, 106 — Interstitial 
Keratitis, 108. 

CHAPTER IX 

Diseases of the Iris and Ciliary Body no 

Congenital Defects, in — Mydriasis, in — Myosis, 111 — 
Iritis, 112 — Cyclitis, 114 — Cysts and Tumors of the Iris, 119 — 
Tuberculosis of the Iris, 120 — Tumors of the Iris and Ciliary 
Body, 121. 

CHAPTER X 

Diseases of the Retina and Chorion 124 

Anemia, 127 — Edema, 127 — Hyperemia, 128 — Hemor- 
rhages, 128 — Detachment, 128 — Retinitis, 128 — Atrophy of 
the Retina, 129 — Rupture of the Retina, 130 — Glioma, 130 — 
Diseases of the Chorioid, 130 — Purulent Chorioiditis, 132. 



CONTENTS . 7 

CHAPTER XI 

PAGE 

Diseases of the Optic Nerve 133 

Papillitis, 133 — Retrobulbar Neuritis, 134— Toxic Ambly- 
opia, 134 — Atrophy of the Optic Nerve, 135. 

CHAPTER XII 

Diseases of the Lens 137 

Cataract, 137 — Luxation of the Lens, 142 — Lenticonus, 143. 

CHAPTER XIII 

Operations for Cataract 144 

Discission, 144 — Extraction, 145 — Iridectomy, 148 — Dress- 
ing, 151. 

CHAPTER XIV 
Recurrent Ophthalmia 155 

CHAPTER XV 

Glaucoma 15 8 

CHAPTER XVI 

Injuries of the Globe 162 

Contusions, 162 — Punctures, 163 — Lacerations, 164 — Com- 
plications, 165 — -Treatment of Injuries of the Globe, 166 — 
Simple Abrasions of the Cornea, 166 — Perforating Wounds of 
the Cornea, 166— Injuries of the Globe, with Foreign Bodies 
Remaining in the Eye, 168— Enucleation of the Globe, 170 — 
Prolapse of the Eyeball, 172. 

CHAPTER XVII 

Fracture of the Orbit 174 

Treatment, 174. 

CHAPTER XVIII 

Parasites of the Eye 176 

Parasites of the Eyelids, 176 — Parasites Found Within the 
Eyeball, 178. 

CHAPTER XIX 

The Principles of Vision 181 

Refraction, 181 — Spheric and Cylindric Lenses, 182 — Acuity 
of Vision, 187 — Accommodation, 188 — Fields, 192 — Scotoma, 
194- 



8 CONTENTS 

CHAPTER XX page 

Errors of Refraction 195 

Hyperopia, 195 — Myopia, 195 — Astigmatism, 196 — Presby- 
opia, 197 — Emmetropia, 197 — Method Used to Determine 
the Refractive Error, 197. 

CHAPTER XXI 

Medicines Used in Ophthalmic Therapeutics 200 

Antiseptic Washes, 200 — Astringents, 200 — Local Anesthet- 
ics, 201 — Caustics, 201 — Mydriatics, 201 — Myotics, 201 — 
Lymphagogues, 201 — Hemostatics, 202 — Ointments, 202 — 
Powders, 202 — Combinations, 202. 

Index 203 



LIST OF ILLUSTRATIONS 



Normal Fundus of a Dog's Left Eye Frontispiece 

FIGURE PAGE 

i . Portion of skull of horse, showing bony orbit 12 

2. Vertical axial section of orbit of horse 13 

3. Vertical section of eyeball of horse 15 

4. Vascular tunic of eyeball of horse, front view 16 

5. Fundus oculi, seen on equatorial section of eyeball of horse. . . 17 

6. Vertical section of anterior part of eye of horse, with lids 

half closed 19 

7. Iris of horse, showing position of the corpora nigra 22 

8. Eyeball of horse in orbit, showing shape of the iris and cor- 

pora nigra 23 

9. Knapp's lid clamp 45 

10, n. Wharton Jones' operation for ectropion 46 

12, 13. Kuhnt-Szymanowski operation 47, 48 

14, 15. Dieffenbach's operation 50 

16, 17. Burow's operation 51 

18. Operation of Anagnostakis and Hotz 52 

19. Cilium forceps 53 

20. Canthoplasty 55 

2 1 . Right eye of horse 60 

22. Dermoid cyst of the cornea 84 

23. Staphyloma of the cornea 103 

24. Protrusion of the globes 106 

25. Carcinoma of the orbit of dog 119 

26. Carcinoma of the orbit of cat 120 

27. Sarcoma of the orbit of horse 121 

28. Tumor of the orbit 122 

29. Melanosarcoma of the chorioid 123 

30. Loring's ophthalmoscope 125 

31. Dislocation of the lens 142 

32. Eye-protector for horse 152 

33. Brusasco's eye-protector for dog. 153 

9 



IO LIST OF ILLUSTRATIONS 



34. Brusasco's eye-protector for dog applied 153 

35. Injury of the globe of horse 165 

36. Enucleation of the eye of horse 171 

37. Principal focus of a convex lens 182 

38. Conjugate focus of a convex lens 183 

39. Virtual focus of a convex lens 183 

40. Principal focus of a concave lens 184 

41. Virtual image of a convex lens. . . 184 

42. Virtual image of a concave lens 185 

43. Image formed by a convex lens 185 

44. Diagram illustrating the visual path and the relation of the 

visual field 192 



OPHTHALMOLOGY FOR 
VETERINARIANS 



CHAPTER I 
ANATOMY OF THE EYE 

"From a point of view of comparative anatomy, an 
eye is any part of an animal body which responds 
more readily than other parts to the special stimulus 
of light, or whose activity is specially excited by the 
impact of light rays." — Century Dictionary. 

In the low forms of life the eye-spots or eye-points, 
.as they are called, differ greatly in number. They 
are rudimentary eyes, and consist in many cases of 
simple pigment spots sensitive to light, and may be 
situated anywhere on the body. 

In insects proper, crustaceans and arachnidians, the 
eyes are well developed and are either simple or com- 
pound. They are usually two in number, but may be 
four, six, or eight. Crustaceans, as a rule, have a single 
pair, which stand out from the head like a cherry upon 
a stem. 

In describing the anatomy of the eye, that of the 

highest order of the animal kingdom will be consid- 

11 



12 



OPHTHALMOLOGY FOR VETERINARIANS 



ered. The higher in the scale of animal life, the more 
nearly is the eye like that of man; the only difference 
is the addition of some conveniences of which man is 
not in need. Most of the quadrupeds, for instance, 
are supplied with a third eyelid, or nictitans mem- 
brane, and a retractor muscle. The former acts as a 




Fig. i. — Portion of skull of horse, showing bony orbit. 



finger to remove foreign bodies, dust, etc., that may 
fall upon the cornea. The latter serves to draw the 
eyeball backward into the orbit and protect it from 
approaching harm. These, together with the varia- 
tions in size, are the only practical differences from the 
human eye. 

The eyes of quadrupeds present nearly laterally, 



ANATOMY OF THE EYE 



13 



and are protected by bony orbits and soft appendages. 
They are embedded in a cushion of fat and surrounded 




Fig. 2. — Vertical axial section of orbit of horse: a, a, Eyelids; b, bulbar 
fascia (Tenon's capsule); c, c', retractor bulbi; d, rectus oculi inferior; 
e, obliquus oculi inferior (in cross-section); /, rectus oculi superior; g, 
levator palpebral superioris; h, obliquus oculi superior (in cross-section); 
i, lacrimal gland; k, k', periorbita; /, superficial fascia; m, deep fascia; n, 
skin; 0, retrobulbar fat; p, extra-orbital fat; q, temporalis muscle; r, supra- 
orbital process; s, cranial wall; 1, cornea; 2, sclera; 3, choroidea; 4, ciliary 
muscle; 5, iris; 6, granula iridis; 7, retina; 7', optic papilla; 8, optic nerve; 
9, crystalline lens; 10, capsule of lens; 11, ciliary zone; 12, posterior cham- 
ber; 13, anterior chamber; 14, conjunctiva bulbi; 15, vitreous body. 
(After Ellenberger, in Leisering's Atlas.) 

or, rather, encased within a capsule, in which they are 
freely moved at will by the aid of the extrinsic muscles. 



14 OPHTHALMOLOGY FOR VETERINARIANS 

The coats of the posterior five-sixths of the globe are 
three in number, and from without inward are called 
the sclera, the chorioid, and the retina. The anterior 
one-sixth is formed by the transparent cornea. 

The eye internally is composed of the anterior cham- 
ber, the iris and ciliary body, the posterior chamber, 
the lens in its capsule suspended by the ciliary liga- 
ment from the ciliary muscle, the vitreous encased in 
the hyaloid membrane, and the optic disk. 

The sclera is a white, tough, fibrous membrane, 
and extends from the optic nerve to the cornea. It 
is really an expansion of the dura mater, which extends 
forward from the skull cavity through the optic foramen 
in the apex of the orbit, and serves, in its course to the 
eyeball, as a sheath for the optic nerve. It is principally 
for protection, and affords attachment for the extrinsic 
muscles. The four recti and the two oblique muscles 
have their attachment anterior to the equator, while 
the retractor muscle is widely expanded over the poste- 
rior third of the sclera, which is its thickest portion. 

The fine fibrillse of which the sclera is composed run 
in two principal directions — from before backward, and 
in a circular direction concentric with the corneal 
margin. 

Anteriorly, the sclera is continuous with the true cor- 
nea. At the posterior portion a few fibers of the inner 
layer penetrate the optic nerve at a junction with the 
trunk of the nerve and its head, and are inserted into 



ANATOMY OF THE EYE 



15 



the connective tissue about the central vessels. This 
portion is known as the lamina cribrosa. The deep lay- 
ers of the sclera contain numerous pigment-cells, more 
pronounced in animals than in man, hence the brown- 
ish or bluish color. It is penetrated by numerous ciliary 




Anterior 
chamber 



Rectus oculi inferior 



Ciliary 
processes 
Chorioii 

Fig. 3. — Vertical section of eyeball of horse, about f . The contour of the 

crystalline lens is dotted. (Sisson, Veterinary Anatomy.) 

vessels at the posterior portion surrounding the optic 
nerve entrance. The anterior portion is connected to 
the conjunctiva by a loose connective tissue, known 
as the episcleral tissue. 
The chorioid, or middle coat, is a vascular and pig- 



i6 



OPHTHALMOLOGY FOR VETERINARIANS 



mentary structure. Its function is to nourish the eye 
and absorb light. It extends from the optic disk to the 
ora serrata. 

Histologically, the chorioid consists of five layers. 
First, from without inward, the suprachorioid, inti- 




Fig. 4. — Vascular tunic of eyeball of horse, front view. The cornea 
is removed and the sclera is reflected in flaps: 1, Sclera; 1', lamina fusca; 
2, choroidea; 2', ciliary veins; 3, ciliary muscle; 4, iris; 5, 5', granula 
iridis; 6, pupil, through which the lens is visible. (After Ellenberger, in 
Leisering's Atlas.) 

mately connecting it with the sclera; second and third, 
are two layers of vessels, large and small respectively, 
embedded in a stroma of connective tissue with numer- 
ous branched pigment-cells; fourth, the lamina ruyschii, 



ANATOMY OF THE EYE 



17 



composed principally of capillaries; fifth, the lamina 
vitrea, which is lined with a layer of pigment epithe- 
lium. Late authorities claim that this pigment-layer 
embryologically belongs to the retina. An absence of 
black pigment on the posterior layer in the carnivora 
affords, a greenish-blue reflex, and is known as the 




Fig. 5. — Fundus oculi, seen on equatorial section of eyeball of horse: 
1, Sclera; 2, choroidea; 3, retina (loosened); 4, tapetum; 5, optic papilla; 
6, optic nerve. (After Ellenberger, in Leisering's Atlas.) 

"tapetum lucidum." This reflex is noticeable in cats' 
eyes in the dark. 

Because of the intimate association of the pigment 
and circulatory layers of this body with those of the 
ciliary body and iris, and from the likeness, as a whole, 
to that of a grape when the sclera is stripped off, this 
portion of the eye — the iris, the ciliary body, and the 
chorioid — is known as the uveal tract or uvea. 

The retina is the internal coat or lining of the eye. 



1 8 . OPHTHALMOLOGY FOR VETERINARIANS 

It is composed principally of nerve elements and is 
practically an expansion of the optic nerve. Its function 
is to receive the image focused by the refractive media, 
which is conveyed through the optic nerve to the sight 
center in the occipital lobes. The retina of the living 
eye is transparent, while that of the dead eye is opaque. 
It also loses its transparency in portions undergoing 
pathologic changes. 

It extends posteriorly from the optic nerve, and ap- 
parently terminates anteriorly at an irregular line, 
known as the ora serrata, posterior to the apex of the 
ciliary body, but "the microscope shows that under 
a similar form it extends still farther, even up to the 
edge of the pupil. It, therefore, lines the inner surface 
of the ciliary body and the posterior surface of the 
iris" (Fuchs). 

Corresponding with the central vision at the poste- 
rior pole lies a small yellowish spot, called the macula 
lutea, a slight depression in the center of which is the 
fovea centralis. 

Histologically, the retina is a very complicated 
structure, and consists from without inward of ten 
layers: i, A pigment epithelial layer; 2, a layer of rods 
and cones; 3, an external limiting membrane; 4, an 
external molecular layer; 5, an external granular layer; 
6, an internal molecular layer; 7, an internal granular 
layer; 8, a layer of granular cells; 9, a layer of nerve- 
fibers; 10, an internal limiting layer or membrane. 



ANATOMY OF THE EYE 
? 4 



19 




17 3 

Fig. 6. — Vertical section of anterior part of eye of horse, with lids 
half closed: 1, Tarsal gland of upper lid; 2, palpebral conjunctiva; j, 
fornix conjunctiva?; 4, levator palpebral superioris; 5, orbicularis oculi; 
6, cornea; 7, anterior chamber; 8, iris; g, g' , granula iridis; 10, posterior 
chamber; 11, ciliary process; 12, ciliary muscle; 13, ciliary zone or sus- 
pensory ligament of lens; 14, chorioid; 15, sclera; 16, lens; 17, root of 
tactile hair. (After Bayer, Augenheilkunde.) 

The pigment epithelial layer is the one before men- 
tioned with the chorioid, which really belongs to the 
retina. The rods and cones are unevenly distributed, 



20 OPHTHALMOLOGY FOR VETERINARIANS 

as the cones only exist in the fovea, while the rods 
become more abundant from the border of the macula 
lutea to the ora serrata, while the cones diminish. 

The retinal vessels enter through the center of the 
optic nerve, expanding and dividing, much like the twigs 
of a tree, through the retinal tissue to the ora serrata 
without anastomosing. These afford nourishment to 
the inner layers, while the outer layers are dependent 
upon the small vessels of the inner layer of the chorioid 
for nourishment. The retinal vessels can be distinctly 
seen by the aid of the ophthalmoscope. 

The cornea comprises about one-sixth of the ex- 
ternal anterior portion of the eyeball. It is a perfectly 
transparent body, and one of the refractive media next 
in importance to the lens. The anterior surface is con- 
vex and the posterior is concave. 

It is composed of five layers. From without inward, 
they are: The epithelial layer, Bowman's membrane, 
the stroma or cornea proper, Descemet's membrane, 
and the endothelium. The epithelium is composed of 
columna, polyhedral and squamous cells, and is con- 
tinuous with the conjunctiva. Bowman's membrane 
is devoid of cells, and is described as an elastic homo- 
geneous membrane. It is strongly adherent to the 
stroma. The stroma is the thickest layer, and con- 
sists of numerous fibrous layers enclosing corpuscles 
similar in structure closely connected by a cement 
substance. The corneal cells proper are fixed non- 



ANATOMY OF THE EYE 21 

motile cells, flat in appearance, and connected to 
neighboring cells by branched processes. A type of 
motile cell, said to be white blood-corpuscles, but few 
in number, float in the lymph-channels of the stroma. 
This portion of the cornea is continuous with the sclera. 
Descemet's membrane is an elastic homogeneous hya- 
loid membrane, and is easily separated from the stroma. 
It is said to be the protecting membrane of the poste- 
rior portion of the cornea because of its elasticity and 
resistance to pathologic processes. The endothelium 
or posterior epithelium, as it is sometimes called, lines 
the posterior portion of Descemet's membrane. It 
is composed of flattened cells of a single layer. 

The cornea has no vessels of its own, but is nourished 
by a network of capillary loops near the border. These 
loops are supplied by the anterior ciliary vessels. 

The iris is practically a diaphragm, much like the 
diaphragm in a camera, with an opening in the center 
called the pupil. It is a dividing membrane between the 
anterior and the posterior chambers, which are filled 
with a watery fluid known as the aqueous humor. 
The pupillary portion of the iris rides on the lens dur- 
ing contraction and dilatation. By reason of the con- 
vexity of the lens the iris is slightly pushed forward 
at this portion. Should the lens be absorbed, dislocated, 
or removed, the iris would be tremulous for want of 
support. This is known as iridodonesis. 

The iris arises from the anterior portion of the 



22 OPHTHALMOLOGY FOR VETERINARIANS 

ciliary body also by a ligament of loose tissue from near 
the posterior portion of the sclerocorneal connection. 
This ligament is called the ligamentum pectinatum. 
It has nearly a semicircular shape, and comprises the 
angle between the sclerocorneal margin and the iris. 
It is the extreme boundary of the anterior chamber 
and a most important structure. 

The iris is described as "a spongy sort of tissue," 
composed principally of numerous delicate blood- 




Fig. 7. — Iris of the horse, showing position of corpora nigra. 

vessels, radiating from the periphery toward the pupil, 
and interspersed with a meshwork of branched and 
pigment-cells. The anterior surface is covered with 
epithelium (except the hollow spaces or crypts), which 
is continuous with that on the posterior cornea. The 
posterior surface is covered with a delicate membrane, 
upon which rests a layer of pigment epithelium. This 
membrane, with its fibers extending in a radial direc- 
tion, constitutes the dilator pupillae muscle. The 



ANATOMY OF THE EYE 



23 



sphincter pupillae is a circular, flat body, located in the 
stroma near the pupillary margin. This muscle con- 
tracts the pupil. 

The posterior layer of pigment epithelium is con- 
tinuous with that of the ciliary body and retina. It 




Fig. 8. — Eyeball of horse in orbit, showing shape of the iris and the corpora 

nigra. 

extends to the anterior margin of the pupil, and in the 
horse it is quite thick in the upper portion, forming 
several prominent projections into the pupillary space. 
These pigment bodies are known as the "corpora nigra," 



24 OPHTHALMOLOGY FOR VETERINARIANS 

and are commonly called "grape-kernels" and "soot- 
balls." The pigment of the posterior layer and that 
in the meshes of the stroma give color to the iris, and 
the varied colored irides depend upon the amount of 
pigment deposited in them. A horse with little or no 
pigment in the iris, is called "wall eyed." Albinos are 
devoid of pigment. The white rabbit is a good example. 
In such cases a pinkish reflex is seen, derived from the 
retinal circulation. 

The pupil varies in size and shape in different animals. 
In fetal life a delicate membrane covers the pupillary 
space, known as the membrana pupillaris. This disap- 
pears a few days or weeks before birth, though in some 
cases portions of it remain in threadlike forms, known as 
a persistent pupillary membrane, which is often mis- 
taken for a pathologic condition. 

The ciliary body is closely connected to the sclerotic 
coat from the ora serrata to a point near the sclero- 
corneal junction. It is composed of muscular fibers, 
connective tissue, blood-vessels, and pigment. The body 
is circular in shape in relation to the sclerocorneal 
margin. By making a vertical or horizontal section of 
the globe the muscle can be studied longitudinally. 
Such a section gives it a triangular appearance. The 
muscle-fibers are of two kinds — the longitudinal and the 
circular. The former comprise the greater portion, and 
lie externally near the scleral tissue, and are called 
Briicke's portion, after the discoverer. The latter form 



ANATOMY OF THE EYE 25 

the internal base of the muscle body and were discovered 
by Heinrich Miiller; hence, it is called Miiller's portion. 
At the anterior zone are folds of connective-tissue 
stroma — seventy or more in number — intermixed with 
numerous blood-vessels and branched pigment-cells. 
The anterior internal portion of the body is continuous 
with the iris. 

A layer of pigmented and one of non-pigmented cells 
lines the body, and these are continuous with the poste- 
rior layers of the iris forward and the chorioid and 
retina backward. This intimate association of the 
pigment, from the optic disk to the pupillary border, 
has given it the name of the uvea. 

The ciliary muscle is the muscle of accommodation, 
and by its contraction the lens becomes more convex, 
shortening its focus, and accommodating vision for 
near work. This and the sphincter and dilator pupillae 
are the intrinsic muscles of the eyeball. 

The lens is the principal refractive medium. It is 
biconvex, perfectly transparent, colorless, circular in 
shape, and is enclosed in a delicate transparent capsule. 
It lies between the iris and the vitreous, where it rests 
in a fossa in the latter substance — the fossa petellaris. 
The space between the border of the lens and the ciliary 
muscle is known as circumlental space. The anterior 
portion supports the pupillary border of the iris. 

The lens is composed of hexagonal prisms, arranged 
in concentric layers supported by a cement substance. 



26 OPHTHALMOLOGY FOR VETERINARIANS 

The center or nucleus is unstriated and becomes scle- 
rosed as age advances. It is supported by the suspen- 
sory ligament or zonule of Zinn. This ligament is com- 
posed of homogeneous fibers, which arise from the 
ciliary body anterior to the ora serrata and the ciliary 
processes, and it is fused with the lens capsule near the 
border. The space between the fibers as they diverge 
is called the canal of Petit, and is triangular in shape 
on transverse section. The capsule is similar in struc- 
ture to the suspensory ligament. The anterior capsule 
has a layer of epithelial cells on the surface next the lens, 
which become associated with the lens substance near 
the zonular portion. The posterior capsule has no 
epithelium. 

Like the cornea, the lens has no blood-vessels of its 
own. It derives its nourishment from the ciliary proc- 
esses. 

The vitreous is a gelatinous substance, perfectly 
transparent and colorless. It fills the vitreous chamber, 
or that portion of the globe posterior to the lens, and it 
is enclosed in a delicate structure called the hyaloid 
membrane. At the anterior portion is a depression in 
which rests the lens. 

The vitreous mass is composed of rounded and 
branched cells. It is devoid of blood-vessels, and re- 
ceives its nourishment from the uvea. In the center 
is a small canal which serves as a lymphatic channel. 
This, in fetal life, was traversed by the hyaloid artery 



ANATOMY OF THE EYE 27 

from the optic disk to the posterior lens capsule. In 
some cases portions of this persist, with an opacity of 
the central portioxi of the posterior capsule, known as a 
posterior polar cataract. 

Should the vitreous become fluid, as it sometimes does 
by reason of disease, the tension of the globe is much de- 
creased and the retina may become detached by loss of 
support. 

The conjunctiva is a mucous membrane, and covers 
the anterior half of the globe, except that portion sup- 
plied by the cornea. It merges with the anterior epi- 
thelium of the cornea, extending over the sclera as far 
as the fornix, where it folds upon itself and lines the 
posterior surface of the lid, and is strongly adherent to 
the tarsus. This portion is called the palpebral conjunc- 
tiva. The bulbar portion is freely movable over the 
sclera, and is connected to it by the loose episcleral tis- 
sue. At the inner angle, in man, is a fold known as the 
plica semilunaris, which is said to be a rudimentary 
nictitans membrane so prominent in animals. Just 
inside of this is a small elevated island of tissue covered 
with hairs, known as the caruncle. 

The nictitans membrane, or "accessory eyelid," is 
situated near the nasal angle, between the globe and the 
side of the orbit. It is composed of elastic fibrocartilage 
and is irregular in form, being thick and somewhat 
prismatic at its base and thin anteriorly, where it is cov- 
ered with a fold of conjunctiva. Posteriorly, it is con- 



28 OPHTHALMOLOGY FOR VETERINARIANS 

tinuous with a pad of fat which is insinuated between all 
the muscles of the eye. Its internal surface is concave 
and its external surface is convex. When the eye is 
in its natural position only the margin of the membrane, 
covered by conjunctiva, is perceptible, the rest being 
buried in the ocular sheath; but when, by contraction 
of the straight muscles, the globe presses upon the pad 
of fat, the membrane is forced out and covers more or 
less of the cornea. This movement, which is instan- 
taneous, is for the purpose of removing any offending 
agent from the surface of the eye. In some diseases, as 
tetanus, the membrane is forced outward and remains 
so. It is vulgarly called the "haw of the eye" (Vaughn). 

The nictitans is very prominent in fowls and birds, as 
well as in quadrupeds generally, while in the inhabitants 
of the sea it is absent. Its function is associated with the 
"gland of Harder," which is a sort of supplementary 
lacrimal gland, and furnishes an abundance of unctuous 
fluid in conjunction with the action of the membrana 
nictitans. It is described as a "reddish-yellow gland," 
and is situated beneath the membrana nictitans, at 
about the middle of its outer portion. 

As these organs are very essential for the protection of 
the cornea, they should by no means be interfered with 
surgically, as is too often done without sufficient reason. 



CHAPTER II 

SYSTEMATIC EXAMINATION OF THE EYE 

The symptoms of pathologic conditions in animals' 
eyes are objective, and, in order to be able to distinguish 
them, one must be familiar with the normal conditions. 
Examine normal eyes at every opportunity; observe 
the particular size and shape of the anterior portion in 
animals of different kinds; see that the lids, iris, con- 
junctiva, etc., are comparatively uniform in size, shape, 
color, and transparency. If one lid droops more than the 
other or is completely closed, it indicates a partial or 
complete paralysis of the muscle that elevates the lid 
-the levator palpebrarum. If the lid fails to cover the 
cornea when the lid is relaxed, the orbicularis palpebrarum 
is involved. Should the lid be closed and raised with 
much resistance, a spasm of the orbicularis exists, pro- 
duced by the presence of a foreign body or from some 
other reflex cause. Examine the border of the lids to see 
that the lashes are properly directed, for if they turn 
inward they act the same as a foreign body. The 
puncta lacrimalia must lie in close apposition to the 
eyeball, otherwise they fail to perform their function 
properly and epiphera will be the result. Projections 

29 



30 OPHTHALMOLOGY FOR VETERINARIANS 

in various portions of the lid indicate the presence of 
tumors. If these are movable and free from the skin, 
a meibomian duct is occluded, resulting in the forma- 
tion of a chalazion. If the lid is edematous, look for a 
point of local induration. This condition may accom- 
pany heart and kidney lesions, and some cases of 
trichinosis. 

The conjunctiva should be transparent, showing the 
sclera beneath it. If it is congested, note carefully the 
location. An injection about the margin of the cornea 
indicates a cyclitis; a localized injection over the site 
of a muscular insertion is a symptom of localized tenon- 
itis; an injection of the peripheral portion, with large 
radiating vessels, suggests glaucoma. 

A severe chemosis suggests either a general tenonitis 
or some affection of the orbital tissues. It sometimes 
occurs with a purulent conjunctivitis. 

The cornea under normal conditions should be trans- 
parent. If it is hazy, determine whether this is super- 
ficial or deep. If the epithelium is intact, and the reflex 
of a window-sash on the corneal surface is not bent or 
broken, the trouble lies posterior to Bowman's membrane. 
It may be due to interstitial disease or to a turbid aque- 
ous and deposits on the posterior corneal layer. 

The pupils should be of the same size, though rarely 
there is a slight difference normally. A large pupil in 
one eye indicates paralysis of the sphincter muscle, the 
use of a mydriatic, or glaucoma. A small pupil indi- 



SYSTEMATIC EXAMINATION OF THE EYE 31 

cates a reflex contraction from the presence of a foreign 
body or corneal ulcer, iritis, or the use of a myotic. 
Paralysis of the sympathetic causes a small pupil in 
both eyes. The pupils should be regular in shape. 
If irregular, iritis is usually the cause. If the pupil is 
not clear, look for a cataract, exudates in the chambers, 
or a turbidity of the vitreous. 

The iris should be clear and lustrous. Both irides 
should be alike in this respect, though a difference in 
the amount of pigment exists in many cases. If the 
iris has lost its brilliancy and has changed its color 
somewhat, an iritis may exist. A tremulous iris is the 
result of loss of support, which is due to displacement 
of the lens, absorption, or previous extraction of the 
same. The iris is subject to cysts, tubercular growths, 
etc. 

The normal lens is difficult to see because of its trans- 
parency; consequently, the pupil should be perfectly 
clear normally, so that light reflected through the 
pupil from the ophthalmoscopic mirror will show a red 
reflex, otherwise there is some opacity of the interven- 
ing media. Any opacity of the lens can readily be seen 
by oblique illumination or by the aid of a strong lens 
with the ophthalmoscope. A lens of 10 diopters will 
disclose floating bodies in the vitreous. A small opacity 
posterior to the lens center will move in the opposite 
direction to the movement of the eye. A complete 
cataract can be seen filling the whole pupillary space. 



32 OPHTHALMOLOGY FOR VETERINARIANS 

Always try the tension of the eye with the bulbs of 
the index-fingers. Place both fingers over the upper 
lid, above the cornea, and make gentle pressure. A 
sense of normal tension can only be acquired by prac- 
tice. An increased tension indicates glaucoma, while 
a decreased tension is the result of a fluid vitreous. 



CHAPTER III 

DISEASES OF THE LIDS 

From without inward the lids are composed of skin, a 
loose areolar tissue, muscle, the tarsus, and conjunctiva. 

The skin is freely movable because of the loose tissue 
beneath it. It is continuous with the skin of the fore- 
head, and blends with the conjunctiva at the margin. 
At this point is a growth of stiff hairs — the lashes— 
which arise from the margin of both lids usually, though 
the lower lid of the dog and pig present no distinct lower 
lashes. 

The tarsus is the framework, and affords the lid firm- 
ness. The upper tarsus is larger than the lower. It is 
not cartilage, but it is composed of dense fibrous tissue. 
The tarsi are connected by the tarsal ligaments to the 
lateral walls of the orbit and to each other by the pal- 
pebral ligaments. It contains the meibomian glands, 
which are about forty in number. These glands are 
arranged in parallel rows, and they have their exit 
through small ducts which open at the margin of the 
lids, posterior to the roots of the lashes. The muscle- 
fibers are those of the orbicularis and, at the upper 
portion, the levator palpebrarum. The fibers of these 

3 33 



34 OPHTHALMOLOGY FOR VETERINARIANS 

muscles run horizontally and vertically and are in- 
timately associated. 

The conjunctiva is the mucous membrane lining the 
lids. It is strongly adherent to the tarsus. Superior 
to the tarsus, it folds upon itself, forming a sort of culde- 
sac, known as the fornix conjunctivae. This portion of 
the conjunctiva contains numerous glands, resembling 
the lacrimal gland in structure.- The mucous glands 
afford a secretion to lubricate the lids in the act of . 
winking and to moisten the cornea. 

The lids contain a portion of the lacrimal apparatus. 
The outlet ducts from the lacrimal gland open at the 
posterior portion of the superior and external part of the 
upper lid. The drainage canals have their origin at 
points known as the puncta lacrimalia. These are 
situated near the inner angle of the lids, nearly opposite 
each other. Small canals run from these, points, and 
these unite at the lacrimal sac, internal to the inner 
can thus. This sac leads into the nasal duct — a bony 
canal— which terminates in the nasal cavity opposite 
the middle turbinate. 

The anatomic arrangement of these structures is 
somewhat different in quadrupeds and fowls. The 
puncta, instead of pin-point openings near the border 
of the lids, are large oval openings in the conjunctiva 
of the lids near the inner portion. The canals are also 
much larger in proportion. 

The outer surface of the lids is subject to the same 



DISEASES OF THE LIDS 35 

diseases as other surfaces of the skin, and often, when 
skin diseases occur about the head and face, the eyelids 
become involved. 

Edema is often a symptom of some remote disease, 
such as the heart or kidneys. It may also be caused by 
local infection, infiltration, and suppuration — the result 
of a blow, fracture of the bony orbit, or rupture of the 
orbital vessels, erysipelas, and other skin affections. 
Trichinosis is also a cause. It is doughy to the touch 
and may pit on pressure. 

Emphysema is due to the escape of air into the cellu- 
lar tissue from fracture of the wall of one of the ad- 
jacent sinuses, and may accompany emphysema of the 
neighboring structures. In this condition a crackling 
sensation is noticeable to the touch. It will subside 
as soon as the cause has been removed. 

Ecchymosis, or "black eye," is due to rupture of 
the subcutaneous vessels and the effusion of blood be- 
neath the skin. It is usually due to direct violence or 
to rupture of remote vessels. Ice-cold applications, 
evaporating lotions, or the lead-and-opium wash may be 
used with benefit. 

Burns are caused by too hot applications, powder 
explosions, fires, caustics, etc. They are divided by 
degree, the same as burns on other portions of the body. 
The treatment depends upon the degree. Those of 
mild degree may be treated with dusting-powders of 
boric acid, etc., while the deeper burns should be treated 



36 OPHTHALMOLOGY FOR VETERINARIANS 

with soothing and antiseptic oils. Powder grains may 
be removed by the application of hydrogen peroxid 
3 parts to glycerin i part. Ordinarily burns may 
be treated upon general principles. In severe cases 
ectropion may follow by reason of large cicatrices, and 
repair will have to be accomplished by plastic opera- 
tions. 

Wounds may be of the incised, lacerated, or contused 
type, and should be treated by general surgical measures. 
The surgery of the eyelid, however, is very difficult, 
when we consider the necessity of adapting well each 
of its important structures. 

Ectropion, or eversion of the lid, is caused by burns, 
injuries, etc., which cause a cicatrix of the skin surface. 
When a severe ectropion exists the eye is very unsightly. 
The conjunctiva is constantly exposed and reddened. 
It becomes greatly irritated and inflamed by exposure 
and want of protection. Ectropion may also be the 
result of paralysis. The lower lid is more often involved, 
in which case the punctum is turned outward, and the 
tears, instead of flowing in their natural channel, flow 
over the cheek (epiphora) and cause much irritation. 
The treatment is principally surgical. 

Entropion, or inversion of the lid, is caused by de- 
structive diseases of the conjunctiva and tarsus. It is 
usually accompanied with trichiasis. Intense irritation 
of the cornea is the result of this condition, and often 
keratitis with opacities follow. The treatment is surgical. 



DISEASES OF THE LIDS 37 

Lagophthalmus, or inability to close the lid, is the 
result of paralysis of the orbicularis palpebrarum, through 
pressure upon or disease of the seventh nerve. Usually 
facial paralysis accompanies this condition when the 
affection of the nerve is posterior to the branches sup- 
plying the orbicularis. Destruction of the cornea may 
ensue by exposure. Temporary relief may be had by 
drawing the lids together, and keeping them closed by 
the use of adhesive plaster. The cause of the paralysis 
should be looked for and removed. 

Ptosis, or drooping of the lid, may be partial or com- 
plete, and is due to paralysis of the levator palpebrarum 
by reason of pressure upon or disease of the third nerve, 
or that portion of it supplying this muscle. It may be 
congenital from absence of the muscle. Injury may also 
be the cause. In all cases of paralysis the treatment must 
be based upon general principles. 

Tarsitis, or inflammation of the tarsus, is the result 
of old trachoma, syphilis, tuberculosis, etc. It is a 
chronic thickening of the tissue, with infiltration of the 
tarsal elements. It may follow chronic infection of the 
meibomian glands. The lid is thick and heavy over 
the site of the tarsus, and oftentimes partial ptosis and 
blepharitis are present. The treatment depends upon 
the cause. Resolvent ointments have been recommended 
combined with massage. In extreme and chronic cases 
the tarsus has been removed. 

Elephantiasis is due to hypertrophy of the skin and 



38 OPHTHALMOLOGY FOR VETERINARIANS 

subcutaneous tissue. It may be confined to one lid only 
or both lids may be affected. It is often the result of 
continued attacks of inflammation of these tissues. 

Blepharospasm is an involuntary contraction of the 
lid. It may be clonic or tonic in character. It is usually 
reflex, and is due to some irritation of the seventh nerve. 
The lid is spasmodically contracted when a foreign body 
is present and also in some diseases of the cornea. The 
mild clonic type is often due to nervous diseases ; chorea, 
habit, etc. In these cases nerve tonics and rest are of 
benefit. In the animal, more likely a foreign body is the 
cause. Remove the cause. 

Ankyloblepharon is a condition in which the edges 
of the lids have grown together. It is usually caused 
from traumatism or disease, or may be due to a con- 
genital defect, when the lids fail to open, as is often 
seen in kittens and other pets. An operation is the 
only relief, though in congenital cases the lids will 
usually separate if one will give nature sufficient time 
to do its work. 

Blepharitis marginalis, an inflammation of the lid, 
is known as blepharitis, but the former term designates 
a local inflammation along the margin. There are two 
principal types — the superficial and the ulcerative. The 
superficial type is manifest by the presence of redness 
and swelling, together with the formation of crusts, 
which usually occur about the lashes, and frequently 
cause them to fall out by slight friction. The hair- 



DISEASES OF THE LIDS 39 

follicles are not involved, and the lashes grow again by 
proper treatment. It often occurs in strumous sub- 
jects, and accompanies catarrhal and other types of 
conjunctivitis and the presence of pediculi. 

In the ulcerative type the above symptoms are 
present, but more severe, together with ulceration, 
which occurs beneath the crusts. This ulceration in- 
vades the hair-follicles, and when the lashes are once 
lost they fail to grow again. It is often due to infection. 
Severe itching is ' often present, and rubbing the lids 
tends to create a fresh focus for the growth of the 
organisms. The lids are heavy and partly closed, and 
the matting together of the lashes with crusts and 
secretion makes the animal look as though it were suffer- 
ing with some severe constitutional disease. 

Treatment. — This should be directed to the cause. 
If conjunctivitis or other diseases of adjacent struc- 
tures exist, they should be met by appropriate thera- 
peutic measures. 

In mild cases soften the crusts with vaselin, and, 
after this has remained on for several hours, wash it off 
with a mild alkaline solution, remove the crusts that 
may remain, and apply an ointment composed of yellow 
oxid of mercury 6 grains, and vaselin 1 ounce. 

In the ulcerative type the above treatment may be 
employed, and when the lids are free from crusts the 
ulcers may be touched with a 2 to 10 per cent, silver 
nitrate solution, the tincture of iodin, or a 25 per cent. 



40 OPHTHALMOLOGY FOR VETERINARIANS 

solution of carbolic acid in alcohol. This treatment 
should be repeated as occasion requires, and care should 
be exercised that none of the solutions get into the eye. 
The general health of the animal should always be 
considered. 

Hordeolum, or stye, is a localized infection about 
a hair-follicle, resulting in suppuration. A stye may 
occur independent of blepharitis, though they often 
occur together. Pain, localized tenderness, and swell- 
ing are the prominent symptoms. In some cases a pro- 
found edema of the whole lid occurs. Styes often ap- 
pear in succession, or two or more may occur at the 
same time. In the late stage of suppuration they tend 
to point and rupture of their own accord. 

Treatment. — Much the same treatment as in blephari- 
tis may be employed. When the stye points it is better 
to open it with a small sharp-pointed instrument and 
express the contents. Protect the opening with a little 
flexible collodion. 

Chalazion. — This is a disease of the meibomian glands, 
situated in the tarsus, and the result of stoppage of the 
outlet ducts which open at the inner edge of the lid, just 
posterior to the roots of the lashes. It is manifest by a 
localized tumor in the lid, movable and free from the 
skin. As the meibomian gland is essentially a sebaceous 
gland, a chalazion is like a sebaceous cyst in character 
and is filled with sebaceous matter. It often goes on 
to suppuration, and may discharge its contents either 



DISEASES OF THE LIDS 41 

through the skin or conjunctival surface. It may, 
however, become absorbed before reaching the stage of 
suppuration and disappear spontaneously, or it may 
remain permanently enlarged and undergo fibroid 
change. Large tumors press upon the eyeball and 
produce much discomfort, besides, they are very un- 
sightly. 

Treatment. — In the early stages the tumor can some- 
times be aborted by gradually milking, or pressing out 
the contents of the duct, and allowing free drainage. 
If suppuration has taken place, the lid may be everted 
and the tumor incised at the place of pointing, and the 
contents scraped out with a small curet. If the tumor 
remains chronically enlarged, as it often does, it is 
better to dissect it out from the skin surface. By this 
method the sac and all may be removed, and there is 
less liability of the tumor recurring. They may appear 
in other portions of the lid or several tumors may co- 
exist. When excised from the outside the parts may be 
brought together with a single stitch and the whole 
covered with collodion. 

Tumors of the Eyelid.— The lid is subject to benign 
and malignant growths. The former are the angioma, 
a vascular tumor, and usually congenital; the granuloma, 
an excess growth of healthy tissue, is nature's attempt to 
heal a wound, which may appear as a flat growth, cover- 
ing a large surface, or a polypoid soft growth at the mouth 
of a sinus, a papilloma or wart on the surface or border 



42 OPHTHALMOLOGY FOR VETERINARIANS 

of the lid, and certain growths of a horny nature about 
these localities. 

The malignant tumors are the sarcoma and the car- 
cinoma. The former occurs in the young, though often 
seen in older subjects, either as a primary tumor or 
extending from sarcoma of the orbit. 

Carcinoma occurs as an epithelial cancer, charac- 
terized by a slow ulceration, like epithelioma in other 
portions. A diagnosis can properly be made only by the 
use of the microscope. The proper treatment in the 
case of all tumors is excision of the same. The malig- 
nant types, especially the epithelioma, have been treated 
by the #-ray with excellent results. 

Ulcers of the Lid. — Ulcers of the skin surface of the 
lid are not infrequent as the result of burns and other 
injuries and local and constitutional diseases. Lupus 
is particularly liable to affect the lid when the skin in 
the immediate region is diseased. Cowpox and other 
skin affections which may attack the lid may be followed 
by ulceration. 

The cause must be treated as well as the ulcers them- 
selves. Cleanliness is one of the main things to observe, 
together with protection and stimulation to healthy 
granulation, as in the treatment of ulcers of other por- 
tions of the body. 

Abscess of the Lid. — This is often phlegmonous in 
character, and is caused by direct injury, diseases of the 
bones in the neighboring region, erysipelas, or anthrax, 



DISEASES OF THE LIDS 43 

The general symptoms of purulent inflammation 
accompany it— edema, induration, swelling, pain, and 
tenderness on pressure. The swelling is so intense as to 
completely close the lid. The pus is diffused through the 
tissues, and gangrenous destruction of the tissues may 
result. This is followed, in the process of healing, by 
cicatrices, which interfere with the closure of the lid or 
produce ectropion. Both lids are often affected. 

Treatment.— As soon. as one can determine the pres- 
ence of pus, a free opening should be made and drainage 
established, hot bichlorid compresses applied, and every 
effort made to get the best results and prevent as little 
deformity as possible in the process of healing. Co- 
existing conditions should always be sought for and 
promptly treated. 

Trichiasis. — This is an abnormal position of the 
eyelashes. They grow inward or backward toward the 
globe, instead of outward. It is often caused by con- 
traction of the inner surface of the e}^elid from diseases 
of the conjunctiva and tarsus. It produces great irrita- 
tion of the cornea by constantly scratching it in the act 
of winking. If this irritation continues, inflammation 
and opacity of the cornea may follow. 

Treatment. — If only a few lashes turn inward they may 
be extracted with a pair of forceps. This operation 
must be repeated at regular intervals, for the short 
stubby lashes that grow again cause more irritation 
than the long silky ones. The hair-follicles may be 



44 OPHTHALMOLOGY FOR VETERINARIANS 

destroyed by electrolysis. If the condition is general 
and accompanied with entropion, as it often is, one of 
several operations may be performed. 

Distichiasis. — This is a double row of lashes on the 
same lid. The posterior row may be removed by special 
operation. 



CHAPTER IV 

OPERATIONS ON THE LIDS 

Operations on the lids are necessary to correct 
certain deformities, such as ectropion, entropion, trich- 
iasis, and ptosis. In doing operations on the lids 
requiring incisions of the external parts in animals the 
hair should be shaved from the part incised, so that it 
will not be caught in the wound when the sutures are 
applied. 

The same antiseptic and aseptic precautions should 
be used as in doing operations on other portions of the 




Fig. 9. — Knapp's lid clamp. (de Schweinitz, "Diseases of the Eye.") 

body, but the operator should be careful that strong 
antiseptic solutions do not enter the inner portion of the 
lids and injure the cornea. The lid clamp or horn 
spatula (Fig. 9) should be placed beneath the lid to 
afford more resistance and firmness when making in- 
cisions and to protect the eyeball. This should be sup- 

45 



46 



OPHTHALMOLOGY FOR VETERINARIANS 



ported and gently raised by an assistant during the 
operation. 

The illustrations of these operations are shown on the 
human eye, and are taken from Dr. de Schweinitz's 
work on "Diseases of the Eye," published by W. B. 
Saunders Co. 

Ectropion. — There are numerous operations for the 
correction of ectropion. One of the simplest is the 
Wharton Jones' operation (Figs. 10 and n). 





Fig. 10. Fig. ii. 

Figs. 10, ii. — Wharton Jones' operation for ectropion, (de Schweinitz, 

"Diseases of the Eye.") 

A V-shaped incision of the skin is made, the apex ex- 
tending downward. The skin is undermined, and the 
central portion elevated, when the whole is brought to- 
gether as shown in Fig. n. This allows a more lax 
condition of the skin of the lid, and is a good operation 
in ectropion following small cicatrices. 

Success has been attained in numerous cases by the 
writer by doing the Kuhnt-Szymanowski operation, which 



OPERATIONS ON THE LIDS 47 

is described as follows by Meller in his work on "Oph- 
thalmic Surgery." He divides the operation into four 
steps: The first step consists in "splitting the lower 
lid in the intermarginal border." He uses a lancet or 
keratome for this purpose, passing it in between the 
skin and the tarsus, using the thumb and index-finger 
as a guide, so that the tarsus or skin will not be wounded. 
He starts "slightly to the inner side of the middle of the 
lid and goes exactly to the external canthus." 



1 Ml^^m, \ 







Fig. 12.— Showing the formation of the triangle of skin, which is later 
removed, (de Schweinitz, " Diseases of the Eye.") 

As the lid is very vascular, hemorrhage must be stopped 
with adrenalin or compression. 

"The second step is the excision of a triangular piece 
from the tarsus." The size of this piece depends upon 
the degree of the deformity. This piece is best excised 
with a strong pair of straight scissors. The overlying 
conjunctiva is, of course, included in the excision. 

"The third step consists in the excision of a triangular 



48 



OPHTHALMOLOGY FOR VETERINARIANS 



piece of skin from the region of the external can thus." 
This excision is first mapped out, and the skin divided 
with a sharp scalpel. 

"The fourth step consists in uniting the open wounds." 
First unite the wound in the tarsus, then apply the 
sutures in the skin of the lid, as shown in Fig. 13. 




1 \ 

Fig. 13. — Showing the condition after the excision of the triangular 
piece of skin and the undermining of the lid, which is turned outward. 
The sutures are in place, (de Schweinitz, " Diseases of the Eye.") 



The object is to unite the parts neatly, and to produce 
traction on the lower lid to hold the tarsus, which was 
everted, in its normal position. 

The sutures may be removed in from five to seven 
days, but it is well to let them remain long enough for 
good union to take place. If the operation is done under 
aseptic precautions, the wounds will heal by first in- 
tention. 

At a meeting of the American Medical Association, 



OPERATIONS ON THE LIDS 49 

in 1909, Dr. S. Lewis Ziegler described a method of "gal- 
vanocautery puncture in ectropion and entropion." He 
uses a special clamp for this purpose, in which the lid 
is fixed; then makes, in ectropion, about six punctures 
of the tarsus at equal distances apart with a special 
galvanocautery tip. For entropion, the punctures are 
made on the skin surface. He has seldom seen any 
reaction following its use. If after the first operation 
the result is not satisfactory, the operation may be re- 
peated in two or three weeks. 

In extensive cicatrices, or in cases of destruction of the 
tissues of the lid, plastic operations are often done to 
restore the lid. Such operations are well illustrated in 
Figs. 14-17- 

The cicatrix or ulcerated surface is excised and new 
tissue supplied by a flap from the cheek or forehead. 
If too much tension is produced in drawing together by 
sutures the wound from which the flap was taken, it may 
be covered with Thiersch grafts. Such grafts are taken 
from the leg usually. The hair must first be shaved and 
the site made as aseptic as possible. A portion of the 
upper surface of the skin is then cut away with a to-and- 
fro motion of the razor. The razor should be flooded 
with normal salt solution, so that the grafts will slide 
off easily without curling. They should be imme- 
diately transferred as soon as all bleeding has been 
stopped. The grafts are then protected with per- 



5° 



OPHTHALMOLOGY FOR VETERINARIANS 









Fig. IS- 
Figs. 14, 15. — Restoration of the lower lid by Dieffenbach's method. 
The diseased tissue has been removed in a triangular flap, a-b-c. This 
defect is covered by a flap taken from the cheek, indicated by the dotted 
lines, b-d, d-e, with the result shown in Fig. 15. The remaining gap 
may be covered with Thiersch grafts, (de Schweinitz, " Diseases of the 
Eye.") 

forated rubber tissue, over which is placed a compress 
of sterile gauze wet with normal salt solution. 



OPERATIONS ON THE LIDS 
6 



5i 




Fig. 16. 




tig- 17- 
Figs. 16, 17. — Restoration of lower lid by Burow's method. The dis- 
eased tissue is removed with the flap a-b-c. The horizontal incision is 
prolonged upon the temple and forms the basis of the triangle a-d-e. 
This flap (B) being removed, the cutaneous flap a-c-d is dissected up and 
drawn inward so that the angle a is sutured at the point b, and a-d forms 
the free border of the lid. c-a is now united with c-b, and d-e with a-e, 
with the result shown in Fig. 17. (de Schweinitz, "Diseases of the Eye.") 

Entropion. — This is mostly confined to the upper 
lid. To correct this it is necessary to cause traction 



52 



OPHTHALMOLOGY FOR VETERINARIANS 



of the skin upward. The Hotz-Anagnostakis operation 
meets the indications (Fig. 18). 

"A transitive incision from can thus to can thus is 
made through the skin and subjacent tissue." The in- 
cision should be slightly curved, and should follow the 
upper border of the tarsus, 6 to 8 mm. above the border 



tfplfgB 

I F 




Fig. 18. — Operation of Anagnostakis and Hotz. (de Schweinitz, " Dis- 
eases of the Eye.") - 

at the center and 2 mm. above the canthi. The wound 
is then separated, and a narrow bundle of the muscle- 
fibers, which run transversely with the upper border 
of the tarsus, is exsected with the scissors and for- 
ceps. Three sutures are applied, one in the middle and 
one at each side, at about equal distances apart. The 
center needle is first introduced through the skin only 



OPERATIONS ON THE LIDS 53 

of the lower portion of the wound, then thrust through 
the upper border of the tarsus and the tarso-orbital 
fascia, as well as the skin at the upper portion. The 
lateral needles are placed in the same manner. A good 
needle-holder should be used in this operation, as well 
as in all operations on the lids (Fig. 18). 

Trichiasis. — The above operation is a very satisfac- 
tory one for the correction of this condition. 

When only a few lashes turn inward they may be 
extracted with a pair of cilium forceps (Fig. 19). The 
lashes may grow again, and the short stubby hairs 




Fig. 19. — Cilium forceps, (de Schweinitz, " Diseases of the Eye.") 

cause much irritation of the cornea if they happen to 
be central. 

Electrolysis is used with success in some cases to 
destroy the hair-follicles. One can make an apparatus 
with three dry cells, two pieces of wire, a needle, and a 
sponge. Connect the batteries, and connect the wire 
with the needle on one end, to the negative pole; to the 
positive pole attach the wire with the sponge on it, and 
the apparatus is ready for use. Pass the needle, parallel 
with the hair, to its root. Wet the sponge and place it 
on the cheek or forehead, after denuding the spot 
of hair. As soon as the contact is made a whitish foam 
will appear about the entrance of the needle. The sponge 



54 OPHTHALMOLOGY FOR VETERINARIANS 

can now be removed and the needle withdrawn, when 
the lash will be easily extracted, root and all. 

When trichiasis is complete, ablation of the hair- 
follicles according to Flarer's method is the best to 
perform. The lid is split posterior to the roots of the 
lashes, and just anterior to the openings of the meibo- 
mian ducts, the full length of the lid, transversely, then 
again split anterior to the lashes, the scalpel meeting 
the bottom of the first incision, just beyond the roots. 
The portion containing the cilia, complete, must then 
be detached, and the wound allowed to heal by granu- 
lation. 

When the palpebral fissure is contracted by reason 
of chronic diseases of the conjunctiva, which often 
causes entropion and trichiasis, an operation known as 
canthotomy may be performed. A pair of straight, 
blunt-pointed scissors is placed horizontally, one point 
beneath the outer canthus and the other above, when 
the tissues between the blades are divided with one 
snip. This relieves the pressure of the lid on the cor- 
nea and relaxes the tension of the border of the lid. 

Caniho plasty is the term used for this operation 
when sutures are applied. These sutures are usually 
used, one at the extreme angle of the wound and one 
above and one below, bringing the conjunctiva and 
skin together (Fig. 20). 

Tarsorrhaphy is performed when it is desired to de- 
crease the length of the palpebral fissure. A small 



OPERATIONS ON THE LIDS 55 

flap, including the hair-follicles, is removed from the 
upper and lower lids, at the outer angle, the length 
of the flaps to be determined by the amount of cor- 
rection desired, and the denuded surfaces are then 
united by sutures. 

Ankyloblepharon. — A complete division of the lid 
may be made at the natural line of separation. Begin 
at the outer canthus, pick up the lid with the fixation 




Fig. 20. — Canthoplasty. (Meyer.) 

forceps, and make a small horizontal slit through the 
lid, being careful not to wound the globe. Pass a small 
grooved director through this opening, and with it gently 
raise the lid from the eye. Pass in a pair of small sharp, 
probe-pointed scissors to the heel, and, directed by 
the probe, divide the lid with one cut, if possible, to 
the inner canthus. Fine silk sutures should be used to 
unite the conjunctiva to the skin, using care that the 
knots remain externally. 



56 OPHTHALMOLOGY FOR VETERINARIANS 

Union readily takes place, and the sutures may be 
removed in about four days. 

One should not be too ready to do this operation, 
as nature may perform her work, if given sufficient 
time, in the case of all pet animals. 

Ptosis. — Panas' operation for ptosis is probably one 
of the most popular. Posey gives an excellent descrip- 
tion of the operation as follows: "Two horizontal 
incisions are made, the lower at the orbital margin, 
and along the top of the flap with a slight convexity 
upward, and not quite an inch long; the higher one a 
little longer, and at the upper border of the eyebrow. 
A flap of the skin and muscle is now dissected from the 
tarsus down to the ciliary border, but the septum 
orbitse (suspensory ligament) of the lid is not disturbed. 
The bridge of tissue between the two horizontal in- 
cisions is undermined without cutting the periosteum or 
septum orbitae. The flap is then drawn up under the 
bridge by means of sutures and fastened to the upper 
edge of the higher incision. When the flap is so fixed, 
the traction tends to cause ectropion, and a suture is, 
therefore, placed at each side, passing deeply through 
the septum orbitae and conjunctiva, but not the skin, 
and it also is inserted in the upper lip of the higher 
incision, so as to correct the tendency to eversion." 



CHAPTER V 
DISEASES OF THE LACRIMAL APPARATUS 
The principal diseases of the lacrimal apparatus in 
the animal are those which affect the lacrimal sac 
and nasal duct. 

Dacryocystitis.-This is an inflammation of the 
lacrimal sac. It may be catarrhal or purulent. In 
the purely catarrhal type the sac becomes somewhat 
thickened and distended. There is considerable ten- 
derness on pressure and the sac is fuller than normal. 
By deep pressure a mucosecretion can be pressed out 
through the puncta, though if the duct is free, that is 
if there is no stenosis, it may be pressed downward 
through the duct. In the purulent type the sac be- 
comes very greatly distended, and is exceedingly tender 
upon pressure. The outlet of the duct is usually oc- 
cluded and the tears flow over the cheek (epiphora). 
If not early treated the case takes on the appearance 
of an abscess, and the wall of the sac ruptures and 
the pus finds an exit through the skin at a dependent 
portion. Oftentimes a permanent fistula is the result 
of this condition. 



57 



58 OPHTHALMOLOGY FOR VETERINARIANS 

If the case is at the point of rupture an incision 
should be made, and, under a local anesthetic, the sac 
may be cureted and a solution of nitrate of silver applied. 
It is well to establish the drainage canal if possible, and 
pass through it a solution of argyrol, then some boric 
acid solution. Keep the sac clean and free from pus. 
Should it become permanently or chronically affected, 
the best thing to do is carefully to dissect out the sac. 
This should be done during the stage of quiescence. 

Stenosis of the Nasal Duct. — This almost always ac- 
companies the above disease, and is due to thickening 
and adhesion of the mucous lining of the duct. In 
man, the duct is probed from above, through the puncta 
— usually the lower one. The point of the probe is 
passed into the punctum in a vertical position, then, 
placed horizontally, it is pushed through the canaliculus 
to the bony wall, then, again in a vertical position, it is 
gently pushed until it engages in the upper portion of 
the duct, when it is forced firmly, but gently, downward 
through the duct. In the animal, the probes used are 
much larger and longer than those used in man, and, 
instead of being inserted from above, they are inserted 
in the outlet of the duct below, opposite the middle 
turbinate bone in the nose. After the point of the probe 
is engaged it is pushed upward to the sac, gently break- 
ing up the adhesions in its course. This operation 
should be repeated two or three times a week, accord- 
ing to the indications. 



CHAPTER VI 

MUSCLES OF THE EYEBALL 

The muscles that move the eyeball are known as the 
extrinsic muscles. In the animal they are seven in 
number — the superior rectus, the inferior rectus, the 
external rectus, the internal rectus, the superior oblique, 
the inferior oblique, and the retractor. This last muscle 
is not present in man. 

All of these muscles, except the inferior oblique, have 
their origin at the apex of the orbit, near the margin of 
the optic foramen. The recti muscles pass forward in 
their respective positions, and are inserted into the outer 
surface of the sclerotic coat. The superior oblique 
passes through a pulley, near the internal angular 
process of the frontal bone, at which place the muscle 
assumes a rounded, tendinous formation; from there it 
passes in an external direction, expands, and is inserted 
into the sclerotic between the superior and external 
recti. The inferior oblique arises from the orbital plate 
of the superior maxillary, passes externally, and is in- 
serted into the sclerotic near the superior oblique, poste- 
rior to the equator. Both of these muscles pass beneath 
the recti in their course horizontally. 

The distance of the insertion of the muscles from the 

59 



6o 



OPHTHALMOLOGY FOR VETERINARIANS 



corneal margin depends upon the animal and the size 
of the eye. In man the recti muscles are inserted from 




Fig. 21.— Right eye of horse: a, Remnants of periorbita; b, levator pal- 
pebral superioris; c, obliquus oculi inferior; d, rectus oculi inferior; e, 
rectus oculi externus; /, rectus oculi superior; g, sclera; g', cornea; h, 
lacrimal gland; i, frontal nerve; k, frontal artery; I, branch of lacrimal 
nerve to gland; m, lacrimal artery; n, zygomatic nerve; o, branch of 
ophthalmic artery; p, branch of oculomotor nerve to obliquus oculi in- 
ferior; q, maxillary nerve; r, infra-orbital nerve; s, posterior nasal nerve; 
t, great palatine nerve; u, small palatine nerve; v, internal maxillary ar- 
tery; w, buccinator artery (cut); x, infra-orbital artery; x', malar artery; 
y, sphenopalatine artery; z, great palatine artery; z', small palatine (or 
staphyline) artery; i, posterior deep temporal artery; 2, 3, stumps of 
orbital margin; 4, facial crest; 5, temporal fossa; 6, foramen lacerum 
orbitale; 7, anterior end of alar canal; 8, posterior opening of same. 
(After Ellenberger, in Leisering's Atlas.) 

7 to 7^ mm. from the cornea, while the oblique muscles 
are inserted much farther back — about 17 to 18 mm. 



AFFECTIONS OF THE MUSCLES 61 

The action of the muscles are as follows: The external 
and internal recti cause the eyebaH to move outward 
and inward respectively, and they balance, so to speak, 
the horizontal movements. The superior rectus causes 
an upward and slightly inward movement, while the 
inferior rectus causes a downward and inward movement. 
The oblique muscles cause the eyeball to rotate on its 
anteroposterior axis. They oppose or balance the 
movements of the superior and inferior recti. 

The retractor is the largest and most powerful muscle 
of the eyeball. It has its origin in common with the 
recti muscles, surrounding the optic foramen, passes 
forward, completely encasing the optic sheath, expand- 
ing in a funnel shape, and is inserted into the posterior 
third of the sclerotic coat. Its function is to pull the eye- 
ball backward. 

The insertion of the muscles are tendinous, and these 
tendons are ensheathed in a fascia, which is in reality 
a portion of Tenon's capsule. 

All the extrinsic muscles, except the superior ob- 
lique and the external rectus, are supplied by the third 
cranial nerve. The superior oblique is supplied by the 
fourth cranial nerve, and the external rectus by the 
sixth cranial nerve. 

Affections of the Muscles 

In man we have many affections of the muscles, be- 
cause the eyes are so placed to produce, in a normal case, 



62 OPHTHALMOLOGY FOR VETERINARIANS 

perfect binocular vision; hence, refractive errors, causing 
a greater effort to see, particularly close objects, tend to 
produce a weakness of one or more of the extrinsic 
muscles, resulting in a turning outward or inward of a 
few degrees of one or both eyes. The condition is hardly 
noticeable, though it is brought out by certain forms of 
examination. 

This may go on and on until the position is easily 
seen by a second person, and the eye assumes the ap- 
pearance of being crossed. He may be able to see with 
either eye singly and normally, but the eye that is cov- 
ered, or not fixing, turns outward or inward, as the case 
may be. He may be wholly dependent upon one eye, 
and the eye that is not used becomes partially blind 
(amblyopic) . 

This is not so in the animal, because of the position 
of the eyes and numerous other reasons. A cross-eyed 
animal is seldom ever seen. They may, however, be 
subject to paralysis of the muscles, by reason of pressure 
upon or disease of the nerves supplying those muscles, 
the same as in man. 

One needs only remember the anatomic relations, ac- 
tion, and nerve supply to determine which muscle and 
nerve is involved. 

Ophthalmoplegia. — This is a condition in which all 
the muscles are paralyzed. There being no resistance, 
the eyeball stands out prominently from the orbit and 
is immobile. The lid may droop (ptosis) because of 



AFFECTIONS OF THE MUSCLES 63 

paralysis of the levator palpebral. TLere is little that 
can be done except to protect the cornea; look for the 
cause and remove it if possible. Usually the trouble 
is in the brain at the nerves' nuclei. When extensive, 
other symptoms of cerebral affection accompany it. 



CHAPTER VII 

DISEASES OF THE CONJUNCTIVA 

Conjunctivitis is an inflammation of the con- 
junctiva. It may occur as a simple congestion of the 
membrane or be accompanied by edema of the tissue, 
with or without secretion, varying in character. It may 
be acute, subacute, or chronic in its nature, and occur 
with inflammation of other portions of the eye. 

Acute Catarrhal Conjunctivitis. — In mild cases the 
conjunctiva of the lids only is affected, while in more 
profound cases the whole conjunctiva is involved, and 
presents a bright red appearance, with enlarged vessels 
radiating on the globe. The swelling of the tissue is 
often intense toward the tarsal fold and the inner angle. 
In some cases small hemorrhagic spots occur which may 
be isolated. These may remain so, though they not 
infrequently coalesce, forming large patches. There 
is an increased lacrimal secretion at first, which later 
changes to a mucopurulent character. In consequence 
of this the inner canthus is constantly moist. The secre- 
tion may flow over the lids and create an irritation of the 
skin and the formation of crusts. In the morning the 
lids are usually stuck together and the lashes are matted 

64 



DISEASES OF THE CONJUNCTIVA 65 

with the secretion. If allowed to continue, it causes an 
inflammation of the margin of the lids and a loss of the 
lashes. 

As a rule, there is not much pain — unless a foreign 
body is present — but there is a tendency to keep the 
eyes closed because of the sensitiveness to light. Itch- 
ing is an almost constant symptom at first, and the 
animal, in attempting to stop it, rubs its head against 
some object, which irritates the eye and makes matters 
worse. 

The subacute type follows the acute, and, if not 
properly treated, lapses into the chronic stage. 

The causes are numerous, though the principal one is 
infection or the introduction of bacteria. Animals may 
get into their eye such substances as chaff, seeds, dust, 
insects, hair, etc., or the eye may be struck with a 
whip or twig. Bacteria may extend to the eye from the 
presence of catarrh and other affections of the nasal 
tract. Strong gases, smoke, glaring light, hot air, cold 
drafts, filthy and damp stabling, and a loss of health 
generally may cause it. It often accompanies in- 
fluenza, pneumonia, glanders, and other diseases affect- 
ing the mucous tracts, and in such cases the same or- 
ganism causing these diseases causes the conjunctivitis. 

Diagnosis. — The extreme redness of the conjunctiva, 
together with secretion, the presence of pupillary reac- 
tion, normal tension, and a clear cornea will serve to 

exclude other conditions. 
5 



66 OPHTHALMOLOGY FOR VETERINARIANS 

Treatment. — The main indication in all cases is to find 
the cause and get rid of that. First examine the eye 
carefully for the presence of a foreign body. This may 
be found in many cases only by the closest inspection 
with condensed light and a magnifying lens. 

If the secretion is purulent in character a smear should 
be made, and this examined with the microscope to de- 
termine what particular organism the inflammation is 
due to. If the eye is sensitive to light, the cornea should 
be examined for excoriations of the epithelium. 

The general condition should always be cared for and 
the eye kept as clean as possible. In mild cases a solu- 
tion of 

Sulphate of zinc gr. j; 

Boric acid gr. xx; 

Distilled water § j. 

Mix. 

is sufficient if dropped into the eye several times a day. 
If the case is a severe one the conjunctival surface may 
be brushed lightly with a 2 per cent, solution of silver 
nitrate, and immediately washed off with a normal salt 
solution or clear water. If no corneal complications 
exist, cold applications are indicated. Strong light 
should be excluded and the animal allowed to exercise 
after sundown. 

Chronic conjunctivitis may follow the acute type, and 
often exists a long time. The conjunctiva is somewhat 
thickened, and the secretion is scanty and of a mucoid 



DISEASES OF THE CONJUNCTIVA 67 

character, and is deposited, in conjunction with the 
secretion of the meibomian glands, at the angle of the 
lids. In some cases there is no secretion and the mem- 
brane is reddened and dry. When this is the case 
increased winking occurs in order to moisten the cornea. 
Winking may be increased also when there is a thick- 
ened secretion, to free the cornea of the mucoid fila- 
ments which stick over the pupillary area and interfere 
with vision. These filaments may also form in folds and 
act as a foreign body in the eye. The lids become heavy 
and drowsy in appearance. The secretion upon the 
margin of the lids may produce a blepharitis. At this 
stage loose lashes drop out, and find their way into the 
eye by rubbing it against some object to relieve the itch- 
ing and burning sensation. The lower lid is often de- 
pressed or everted and the tears flow over the cheek, 
because the lower punctum is drawn away from the 
globe. 

This type is often seen in animals that are in poor 
health. Pasturing in low and damp lands is said to 
cause it even in young foals. Dust, wind, smoke, and 
irritating gases are common causes. It is often asso- 
ciated with skin diseases about the head and face. 
Duane says, "Usually the chronic form of conjunctivitis 
(in man) is that produced by the diplococcus of Morax- 
Axenfeld. There may be very little injection of the 
conjunctiva, no swelling of the latter, and little or no 
secretion." On the other hand, the writer has seen 



68 OPHTHALMOLOGY FOR VETERINARIANS 

several cases of conjunctivitis caused by this organism 
which were of a severe purulent type. This shows that 
even in the eye there is a difference in the degree of 
virulence of bacteria of the same kind. 

The treatment is practically the same as in acute 
conjunctivitis. If little or no secretion exists, a solution 
of alum or zinc sulphate in about 1 of i per cent, 
acts favorably, or the conjunctiva may be gently rubbed 
with the alum stick every day or two. Zinc sulphate 
is a specific in conjunctivitis caused by the Morax- 
Axenfeld bacillus. Glycerin tannate brushed over the 
conjunctiva is desirable in some cases. If crusts form 
about the margin of the lids, apply the yellow oxid of 
mercury ointment every night, and wash it off the next 
morning with a solution of bicarbonate of soda. This 
will soften the crusts, when they can be more easily 
removed. It also prevents the lids from sticking to- 
gether, and allows the secretion to flow out, if there is 
any. The general health must be taken into considera- 
tion, and any unhygienic condition of the stable or 
pasture must be corrected. 

Purulent conjunctivitis is also known as purulent 
ophthalmia, and in many cases resembles an acute 
catarrhal conjunctivitis, accompanied with more edema 
of the conjunctiva and an excess of purulent secretion. 

It is caused by a variety of pyogenic organisms, but 
the more common cause in man is an infection with 
gonorrheal pus, when it is spoken of as gonorrheal 



DISEASES OF THE CONJUNCTIVA 69 

ophthalmia. Law says, "Moller records a widespread 
epidemic of gonorrheal ophthalmia in dogs in Berlin 
and environs in 1883." As a rule, animals seem to be 
exempt from infection of the gonorrheal pus of man, 
though Frohner succeeded in infecting the eye of a dog 
from such a source. Horses, dogs, cattle, sheep, and 
swine are susceptible to purulent ophthalmia. 

Crowded and filthy conditions are, as a rule, the 
cause, and if pyogenic organisms find their way into the 
eye the chances are a purulent conjunctivitis will follow, 
as there is no better medium for the development of such 
bacteria. 

Cases may be sporadic, though epidemics occur 
among animals in closely crowded quarters. One ani- 
mal may be the cause of the infection of a whole herd, 
as hundreds of cattle have been attacked in a few days 
through the introduction of one case among them. 

In cases of the so-called "enzootic ophthalmia" 
animals are said to be exempt from succeeding attacks, 
probably from an established immunity. 

The symptoms, at first, resemble an acute catarrhal 
conjunctivitis, but soon the true nature of the case is 
manifest by the presence of pus, which is thin and 
mucoid at first, but later it becomes thick and greenish- 
yellow in color. The swelling of the conjunctiva and 
lids is often so intense that it is difficult to separate the 
lids sufficiently to examine the eye properly. 

If the disease is not controlled the corneal epithelium 



70 OPHTHALMOLOGY FOR VETERINARIANS 

becomes softened by maceration and erosion, and ul- 
ceration of the cornea follows. The bacteria may burrow 
into the deep structure of the eye, causing inflammation 
of these parts and probably the loss of the eye. 

Treatment. — Cleanliness and antiseptic applications 
are the principal indications. First wash the eye with 
a saturated solution of boric acid, then drop in a 25 per 
cent, solution of argyrol. In a few minutes wash this 
out and carefully remove the shreds of pus which the 
solution has coagulated. Then apply another drop, 
and allow it to remain. Repeat this operation every 
three or four hours or oftener if necessary. After the 
secretion has been controlled, use a weaker solution less 
often applied. A 2 per cent, solution of silver nitrate 
brushed over the everted lids, and immediately washed 
off, is of benefit in many cases. If this is used, one ap- 
plication a day is sufficient. If there is much swelling 
of the lids an ice-cold application, frequently repeated, is 
of value. It should not be allowed to remain long 
enough to become warm, for, in that case, it acts as a 
poultice, and encourages the growth of the bacteria. 
If the cornea is involved, hot applications should be 
used. Encourage the animal to keep the eye open as 
much as possible to prevent corneal complications. This 
can be accomplished to a great degree by isolating it in 
a clean, darkened stall, and frequently cleansing the eye 
of the secretion, which causes a reflex closure of the lids. 

When one eye only is affected, the other eye should 



DISEASES OF THE CONJUNCTIVA ;i 

be protected with a pad after it has been thoroughly 
cleansed with an antiseptic solution. 
_ Conjunctivitis during attacks of cow- and sheep-pox 
is due to the same pathologic conditions that exist in the 
skin. This type is most virulent. The lids are extremely 
swollen and the secretion is usually profuse. The char- 
acteristic lesions on the conjunctiva tend to coalesce 
forming a large area of ulceration. If it is not early 
controlled it may terminate in ulceration of the cornea 
perforation, and loss of the eye. 

The treatment is the same as for purulent conjuncti- 
vitis, together with that for ulceration of the cornea 

Phlyctenular Conjunctivitis.-This is vesicular erup- 
tion of the conjunctiva, and often accompanies eczema 
and other skin affections. The vesicles vary in size 
from a pin-point to a pin-head or larger. They may 
be single or multiple. A favorite site is near the corneal 
margin. They often invade the cornea, when it is known 
as a phylctenular keratitis. The vesicles contain 
a semifluid of yellowish appearance, said to be due to 
the presence of staphylococci, but late investigators 
show that tubercular infection may be the cause. The 
apex of the vesicles break down, when they may ter- 
minate in resolution or ulceration. 

One afflicted with phlyctenular disease of the cornea 
or conjunctiva shows typic symptoms in many cases. 
There is much photophobia, and strong contraction of 
the muscle closing the eye, and the head is carried in 



72 OPHTHALMOLOGY FOR VETERINARIANS 

a bowed position. The phlyctenules have a grayish or 
yellowish appearance, and are often supplied with numer- 
ous blood-vessels branching toward them. As the dis- 
ease occurs principally in scrofulous subjects, we often 
have malnutrition, enlarged lymphatics, eczematous 
crusts about the nose and ears, and blepharitis margin- 
alis with crust formation. In very mild cases most of 
these are absent, and only a mild irritation of the eye 
is noticeable. 

As many of the mild cases seem to be caused by errors 
of diet, a regulation of this alone will often effect a cure. 
In all cases of malnutrition suitable tonics should be 
given to tone up the system. Skin affections should be 
appropriately treated. Mild antiseptic colleria may be 
used, and when ulceration has taken place the yellow 
oxid of mercury ointment is of great benefit applied 
three times a day. 

Trachoma. — This disease is principally confined to 
man, though monkeys are subject to it. It was known 
in the far eastern countries centuries before the time of 
Christ. It is the disease which at the present time 
checks foreign immigration, and close inspection is 
made of the eyes of all immigrants before landing on 
our shores. Some, no doubt, escape detection, for it 
prevails principally among the foreign population, nota- 
bly Hungarians, Italians, and the lower class of Jews. 
It is often seen in persons of a higher class. It is one 
of the diseases that causes a large percentage of blindness. 



DISEASES OF THE CONJUNCTIVA 73 

It is no doubt due to some form of bacterium which 
has not yet been definitely settled upon. The writer 
has recently examined several cases by culture growth 
under the strictest precautions, and found a bacilli 
resembling the Klebs-Loffler in nearly all their pe- 
culiarities. The disease is said to be contagious by 
some, but this is doubted by others. It attacks the 
scrofulous, debilitated, and otherwise poorly nourished, 
though the writer has seen it in those who are well 
nourished, lead outdoor lives, and have sanitary homes. 

It is confined principally to the palpebral conjunctiva, 
and usually involves both eyes. The initial symptoms 
are much like those of a catarrhal conjunctivitis, and 
in many cases the disease is well advanced before the 
patient is aware of its real nature. A secretion is de- 
veloped of a mucopurulent character and follicles are 
numerous. These resemble sago grains, and are confined 
to the lymphoid structure. They eventually break down, 
discharge, and cicatrize while others are forming. A 
gritty feeling is experienced in the act of winking, and, 
by reason of this and an extension of the disease, the 
upper part of the cornea becomes irritated and inflamed. 
This is known as pannus. The thickened tissue produces 
a slight drooping of the lid. When the conjunctiva is 
exhausted by extensive ulceration and cicatrization a 
degree of contraction takes place, and the border of the 
lid is drawn inward, producing an entropion. This is 



74 OPHTHALMOLOGY FOR VETERINARIANS 

more so when the tarsus is involved. The disease 
usually becomes chronic. 

Treatment. — To obtain the best results treatment 
should be commenced early in the disease. If the fol- 
licles are full and numerous the radical treatment is 
the best. This consists of an expression, or squeezing 
out, of the follicle contents with a Knapp's or Prince's 
forceps. The conjunctiva is then scrubbed with a solu- 
tion of corrosive sublimate of i : iooo or even i : 500 
parts, and then washed with distilled water. Iced anti- 
septic applications for twenty-four hours will allay the 
reaction. When the conjunctiva has recovered, and 
there is a tendency to recur, it may be rubbed lightly 
every second day with a crayon of sulphate of copper. 
If the secretion persists, argyrol in 25 per cent, solution 
may be used, applied every three or four hours, or silver 
nitrate in 2 per cent, solution, used as in purulent 
conjunctivitis. 

Cleanliness and freedom from secretion are the 
indications, together with stimulation to enhance 
resolution. Boric acid, aristol, calomel, etc., are used 
as dusting-powders and also in the form of ointments. 
The #-ray has been employed with benefit. 

Follicular conjunctivitis resembles an ordinary catar- 
rhal conjunctivitis, with follicles in the retrotarsal fold 
and in the fornix. They are arranged in clusters or 
rows parallel to the lid margin. It is principally con- 
fined to the young, is said to be infectious, and appears 



DISEASES OF THE CONJUNCTIVA 75 

periodically. Some physicians make no distinction 
between this disease and true trachoma, but it is, with- 
out doubt, a distinct disease. It responds readily to 
simple treatment, while trachoma is most obstinate. 

Xerosis of the conjunctiva is a dry condition, and is 
due to the action of a bacterium known as the xerosis 
bacillus. It is a short bacillus, often appears in pairs, 
end to end, sometimes broader at one end, and in many 
cases resembles the Klebs-Loffler bacillus. 

The disease attacks those suffering from malnutrition. 
It is scarcely seen in robust animals. It accompanies 
other diseases — trachoma — and is nearly always pres- 
ent in wasting diseases, near the point of death, and in 
old and poorly fed beasts. It extends to the whole 
surface of the conjunctiva and both eyes are involved. 
There is a scanty secretion of a foamy nature deposited 
upon the margin of the lids and at their angles. This 
secretion contains the bacilli in large numbers. The 
character of the secretion, the dryness of the conjunc- 
tiva, and the loss of brilliancy to the cornea — which 
has a dull, greasy appearance — are the principal symp- 
toms. 

As the disease accompanies malnutrition, suitable 
tonics and a supply of sufficient food of a proper quality 
should be given. When it occurs with other diseases 
of the conjunctiva these should be met with proper 
treatment. In wasting diseases the condition is beyond 
repair, and death only relieves the victim. 



76 OPHTHALMOLOGY FOR VETERINARIANS 

Membranous Conjunctivitis. — This occurs in both 
man and beast. Fowls are particularly susceptible to it. 
It not only attacks the eye of the fowl, but also the 
mucous tract of the nose, mouth, and throat. This 
condition in the fowl is known by the common name of 
"roup," and is allied to diphtheria in the human family. 
The membrane is grayish- white, and in some cases is of 
a thick, yellowish, cream color. It is usually thick and 
tough, strongly adherent, invades the deep structures, 
and extends to the sinus about the orbit. The fowl is 
listless, often standing with its head drooped and un- 
conscious of its surroundings. When the general sys- 
tem becomes invaded with the toxemia, the fowl refuses 
to eat or drink and much loss of weight takes place. If 
the eyeball becomes involved, as it often does, the loss 
of the organ follows. The membrane is so profuse as to 
protrude between the lids, and in one case the writer 
saw it perforated the upper lid, producing a large cica- 
trix after healing. It is said to attack choice varieties 
of fowls particularly. 

Cats, calves, and sheep are susceptible to diphtheritic 
infection. There are forms of bacteria resembling so 
closely the true Klebs-Loffler bacillus it is with difficulty, 
and only by certain biologic tests or characteristics, 
they can be differentiated. In 1884 Loffler described 
two special types in animals — the Bacillus diphtherias 
columbrarum and the Bacillus diphtherias vitulorum. 
The former he obtained from the pseudomembranes 



DISEASES OF THE CONJUNCTIVA 77 

"in the mouths of pigeons, dead from an infectious 
form of diphtheria which prevailed in some parts of 
Germany among these birds and among chickens." 
The latter he obtained "from the pseudomembranous 
exudation in the mouths of calves suffering from an 
infectious form of diphtheria." Because these organ- 
isms differ in many respects from the true Klebs-Loffler 
bacillus, it does not indicate that they are less dangerous 
to man. We believe that this and many other diseases 
are imparted to the human being through the lower 
animals. For this reason, pet animals, when suffering 
with diseases of the eyes of a membranous nature, 
should be isolated from children, for these are the very 
parts handled and stroked by their innocent hands, and 
they unconsciously become infected by wiping their 
own eyes. The result may be a severe conjunctivitis of 
the child's eyes, possibly the loss of an eye, or even the 
loss of life. Law quotes several cases of infection of the 
human being from fowls suffering with membranous 
conjunctivitis. "Four attendants contracted the dis- 
ease from sick fowls at a time when no other cases 
existed in the human population. Diphtheria prevailed 
in fowls, and soon, also, in those who fed them. A 
diphtheritic chicken conveyed the disease with fatal 
effect to a child which fondled it." 

With this and other testimony in favor of the con- 
tagiousness of membranous affections of the conjunctiva 
of chickens, it is best to isolate them from the rest of the 



78 OPHTHALMOLOGY FOR VETERINARIANS 

flock, and also from members of the household, especially 
children. 

There is a stage of exfoliation in which much of the 
membrane can be easily removed; but if this cannot be 
done without causing bleeding of the tissues beneath 
it should not be attempted. Numerous remedies have 
been recommended. Corrosive sublimate solution in 
i : 2000 or even i : iooo parts has been used without 
injury to the cornea. Carbolic acid in suitable strength 
or a saturated boric acid solution is of value. Some 
use kerosene oil with good results. Antitoxin has 
been used satisfactorily. Give the chicken soft foods 
or milk, as grain causes irritation of the mucous tracts 
if the membrane has extended to the mouth and throat. 
With an ordinary chicken the best course to pursue is 
to cut its head off and bury it, but with a prize chicken 
of great value it is a different proposition. 

Pinguecula. — This is a slight elevation of the con- 
junctiva or subconjunctival tissue, just a few milli- 
meters from the internal border of the cornea. It was 
formerly supposed to be a fatty growth, hence its name. 
It is reddish-yellow in color, and at times becomes 
inflamed, when it causes much discomfort. Just what 
its cause is no one seems to know. Errors of refrac- 
tion, dust, and strong wind are supposed to be the 
cause. 

When in a quiescent state they are not troublesome, 
but when inflamed they are very annoying. Astringent 



DISEASES OF THE CONJUNCTIVA 79 

colleria are beneficial. If persistent they may be ex- 
cised. 

Tuberculosis of the Conjunctiva.— This appears ordi- 
narily in the form of ulcers in the palpebral conjunctiva, 
though it may spread to the conjunctiva of the globe 
and even to the cornea. The ulcerated surfaces are 
covered with grayish-red granulations, about which 
are numerous nodules. The whole lid becomes affected 
in severe cases. 

The disease may be primary and only affect one eye, 
though it often accompanies or leads to general infection. 
The neighboring lymphatics are usually involved. The 
cause is local infection, and it is nearly always confined 
to the young. 

Excision of the ulcers, followed by the use of the 
actual cautery, is the best treatment. Iodoform, in 
powder or ointment, is of value, and good results have 
followed the injection of tuberculin. 

Pterygium. — This is an encroachment of the con- 
junctiva of the globe upon the cornea. Its usual site is 
at the inner margin. It may be unilateral or bilateral. 
The growth extends in some cases over the pupillary 
area. It is said to arise from a pinguecula and expo- 
sure to strong winds. 

As a rule it is not inconvenient, unless it has made 
much progress over the cornea, when symptoms of irri- 
tation and traction occur. The vascularity and thicken- 
ing of the tissue are usually great, though in some cases 



So OPHTHALMOLOGY FOR VETERINARIANS 

the growth is extremely thin and only slightly vascular. 
If much traction is made the movement of the eyeball 
is interfered with, and astigmatism may result or even 
diplopia. 

The true pterygium is loosely adherent except at 
the apex, and, being folded in upon itself at the corneal 
margin, a probe may be passed beneath it to the fold at 
this point. This serves to distinguish it from a false 
pterygium — one caused by injury. The latter is strongly 
adherent all along its course. 

The only thing to do is to excise them. There are 
several methods, but the simplest one is as follows: 
Grasp the apex of the growth with a delicate forceps, and 
dissect it carefully to the corneal margin; then make a 
V-shaped excision of the pterygium — the apex of the V 
toward the inner can thus. Undermine the conjunctiva 
so that the remaining edges can be drawn together by 
sutures, using care that it does not overlap the cornea. 
Precede the operation with the usual antiseptic precau- 
tions and two or three applications of a 5 per cent, 
solution of cocain. Some cases recur. 

Foreign Bodies in the Conjunctiva and Cornea. — 
Vegetable substances are commonly found in the folds 
of the conjunctiva, such as seeds, particles of hay, barbs 
from grain heads, etc. The writer saw a small seed which 
had caught in the conjunctiva, had become covered 
with mucus, and, when removed, was in a state of ger- 



DISEASES OF THE CONJUNCTIVA 81 

mination. Chips or twigs of wood, bits of stone, and 
grit are often found in the eyes of animals. 

Pain with increased lacrimation, redness of the con- 
junctiva, and sensitiveness to light are the principal 
symptoms. If the body is located on the conjunctiva 
of the upper lid the act of winking brings it in contact 
with the sensitive cornea and causes increased pain. 
The tears flow over the cheek because there is a greater 
quantity secreted than the little ducts can take care of. 
If allowed to remain, the cornea becomes irritated and 
scratched, and ulceration of this body may arise. If 
the foreign body is on the cornea the conjunctiva of the 
upper lid becomes irritated and inflamed by reason of 
the friction, and a catarrhal or purulent conjunctivitis 
may follow. 

The nictitans membrane is a wise provision for the 
spontaneous removal of foreign bodies and the protec- 
tion of the anterior portion of the eye. The retractor 
muscle acts as a protector from advancing injury by 
drawing the eyeball backward. The lashes have the 
function of catching dust and small objects that would 
otherwise enter the eye and cause inflammation. 

Treatment. — The principal object in treatment is to 
find the foreign body and remove it. This should be ac- 
complished with some degree of nicety. If it cannot be 
readily seen, evert the lower lid by making traction 
downward with the thumb. If it is still not seen, grasp 
the upper lashes with the thumb and index-finger, and 



82 OPHTHALMOLOGY FOR VETERINARIANS 

place the index-finger of the other hand, or a probe, 
about midway between the margin and the upper por- 
tion of the lid, as a fulcrum, and lift the lid upward. 
This will evert the lid and it can easily be inspected. 
If a foreign body be seen, wet with an antiseptic solu- 
tion a small piece of cotton, and, after squeezing out 
the excess of fluid, wipe away the body. Sometimes the 
foreign body may become lodged in the retrotarsal fold; 
in such cases make a small swab by twisting a piece 
of cotton on the end of a probe, wet this and sweep 
it under this portion of the lid, when it will be dislodged. 
The foreign body may be hidden in the folds about the 
inner canthus and nictitans membrane, when only the 
most careful search will reveal it. 

When a foreign body is on or embedded in the cornea 
it requires the most careful treatment. First, try a 
small piece of cotton, well twisted and free from loose 
fibers, and quickly wipe over the body, when, in many 
cases, it will become caught in the cotton and removed. 
It if cannot be readily removed by this method, use a 5 
per cent, solution of cocain, and with a small knife- 
needle gently prick about the body and remove it, 
doing as little damage to the corneal epithelium as pos- 
sible. If the epithelium is much roughened by this 
operation, smooth it gently with an eye spatula or the 
smooth, rounded portion of a shell spoon. Of course, 
strict antisepsis must be observed in all cases. The 
writer has seen severe corneal ulcers and loss of vision 



DISEASES OF THE CONJUNCTIVA 83 

from the careless removal of foreign bodies from the 
cornea. 

Burns of the Conjunctiva and Cornea. — Horses at- 
tending fire engine companies, those used in warfare, 
and animals confined within burning buildings are liable 
to receive direct burns from firebrands, explosions, etc. 
Chemical burns are caused by strong corrosives, such 
as lime and acids, splashed into the eye. 

According to the degree, the symptoms vary from a 
mild redness of the conjunctiva to a complete exfolia- 
tion of this tissue. It may be confined to a small area 
or engage the whole conjunctiva and cornea. Pain is 
always present. In some cases the conjunctiva is gray- 
ish-white in color, particularly during the stage of 
sloughing. The cornea is nearly always involved in 
severe cases, and becomes opaque, like ground glass in 
appearance, and the return to its normal transparency 
depends upon the depth of the burn. The subsequent 
effects of a burn of the conjunctiva and cornea are al- 
ways to be dreaded, although the immediate symptoms 
may not appear to be profound. For this reason one 
should be -guarded in his prognosis. Adhesions, either 
partial or complete, may take place between the con- 
junctiva of the lid and that of the globe, causing limited 
motion. The cornea also may be permanently opaque 
and blindness follow. 

As the pain at first is intense, a drop of a 5 per cent, 
solution of cocain applied to the conjunctiva, with ice- 



84 OPHTHALMOLOGY FOR VETERINARIANS 

cold compresses over the lid, will allay it sufficiently to 
make an examination. Carefully remove any foreign 
substances and flush the eye with sterile water or boric 
acid solution. If the burn is caused by a strong caustic, 
neutralize it with a suitable solution. Olive oil, with the 
alkaloids of atropin and cocain, are of value in relieving 
pain, putting the accommodation to rest, and prevent- 
ing adhesions by allowing the lid to play more freely over 
the globe in the act of winking. An adhesion (symbleph- 




Fig. 22. — Dermoid cyst from original specimen. 

aron) may be prevented to a great degree by daily 
breaking it with a small blunt probe. If extensive ad- 
hesions occur, surgical treatment is necessary. 

Tumors of the Conjunctiva. — These are benign and 
malignant. The former interfere with the function of 
the eye by pressure. The latter usually cause the loss 
of the eyeball, and may endanger life by extension. 

The principal benign tumors are polypi, cysts, lipomata, 
and granulomata. 

A polypus is a pear-shaped tumor, pale and red in 



DISEASES OF THE CONJUNCTIVA 85 

color, bleeds easily by friction, and is found usually in 
the region of the caruncle. 

A cyst may arise as the result of an injury, or "may 
form from dilated blood-vessels or lymph-vessels, or 
from the sac of a cysticercus cellulosse." A type of 
cyst sometimes seen at the junction of the cornea is 
called a dermoid cyst, and is always congenital (Fig. 22.) 

A lipoma, or fatty tumor, is a congenital growth, and 
is seen under the conjunctiva, usually in the upper and 
outer portion. 

A papilloma, or warty growth, is more frequently 
seen springing from the margin of the conjunctiva and 
lid. 

A granuloma, known commonly as "proud flesh," is 
the result of traumatism, and usually springs from the 
point of injury. It is often seen at the mouth of a sinus, 
and should not be confounded with a pathologic growth. 
It is simply an excess of healthy tissue and may be ex- 
cised. 

The principal malignant tumors are the sarcomata 
and carcinomata. 

A sarcoma may grow from any point of the conjunc- 
tiva, but usually the seat is near the margin of the cornea. 
It bleeds easily because of its great vascularity, and is 
often pigmented. 

A carcinoma, or cancer, is not infrequently seen in the 
region of the above tumor. It becomes papillomatous in 
its appearance and is devoid of pigment. In course of 



86 OPHTHALMOLOGY FOR VETERINARIANS 

time its malignancy is marked and destructive processes 
ensue. 

The treatment of all tumors is a complete excision of 
all the tissue involved. The malignant types often re- 
quire an enucleation of the eyeball, and in some cases 
all the tissues in the orbit must be removed (exentera- 
tion) . 

Inflammation of the Nictitans Membrane. — This 
occurs often in conjunction with conjunctivitis, though 
it may occur without inflammation of adjacent struc- 
tures. The membrane may be only slightly inflamed, 
or it may become severely inflamed, swollen, and 
edematous to such an extent as to completely cover the 
cornea. It is usually due to traumatism. It often 
becomes chronically hypertrophied, which greatly in- 
terferes with its function and the closure of the lids, and 
when the advancement is very great it covers the pupil- 
lary area and shuts off vision. 

The excision of this body should be the last thing 
resorted to. Keep the eye clean with antiseptic and 
astringent washes and use antiseptic ointment for 
lubrication. Be particular to examine the body care- 
fully for foreign bodies which may be lodged within 
its folds or beneath it. Hot applications every two or 
three hours are beneficial, followed by astringent col- 
leria. If, after diligent treatment, the body remains 
hypertrophied, that portion externally may be excised, 
being careful to leave that part of it that sweeps over the 



DISEASES OF THE CONJUNCTIVA 87 

cornea, together with the muscles that control it. After 
such an operation contraction readily takes place, and, 
as a rule, it resumes its normal size. In cases of edema 
only several punctures in the outer portion allows the 
escape of serum. This should be followed by cold 
applications frequently applied. 

Edema of this body, together with the conjunctiva of 
the globe, is often symptomatic of some remote trouble, 
"such as purulent inflammation of the orbital tissues or the 
hidden sinuses. In the former case there is more or less 
proptosis or bulging of the globe. 

The membrane is sometimes drawn over the cornea 
spasmodically in cases of tetanus. 



CHAPTER VIII 

DISEASES OF THE CORNEA 

The cornea is one of the most important structures 
of the globe. It is perfectly transparent, and is one of 
the refractive media next in importance to the lens. 
Diseases of this body, resulting in opacity, cause a 
greater percentage of blindness than diseases of all 
other portions of the eye combined. 

It is composed of five layers, and a knowledge of these 
layers (see Anatomy), with the ability to distinguish 
the seat of the disease, will assist one materially in his 
prognosis. 

Keratitis is an inflammation of the cornea. It may 
be local and confined to a small area, or it may be general, 
involving the whole corneal structure. Superficial 
keratitis, in which the epithelium only is involved, may 
undergo complete repair, with much damage to the re- 
fractive value. When Bowman's membrane is destroyed 
it is never replaced. When localized destruction of the 
true corneal layer occurs it is filled in by cicatricial tissue 
quite different in arrangement from normal elements. 

In severe types of keratitis there is also a congestion 
of the conjunctiva, and often an inflammation of the iris 

88 



DISEASES OF THE CORNEA 89 

and ciliary body, with an exudate in the anterior cham- 
ber. This exudate may be purulent in character, when 
it is called a hypopyon. The amount varies from a 
slight line, which can barely be seen, to a complete 
filling of the chamber. The consistence of this exudate 
also varies from a thin, watery fluid to a thick, pultaceous 
mass. The former is readily absorbed, while the latter 
may undergo a fibrinous change and cause adhesions be- 
tween the iris and the cornea. 

Small spots of infiltration and superficial nebulas 
can readily be detected by the use of oblique illumination 
and a magnifying lens. Dense opacities can easily be 
seen without these means. In a recent infiltration there 
is a dull and clouded appearance over the area. In 
case of an ulcer there is a loss of substance, seen in mild 
cases, by a break in a reflected line on the surface of the 
cornea. If the surface retains its luster the ulcer is a 
clean one, but if there is a cloudiness over its area, it is 
a foul or infected one. An opacity with a lustrous 
surface indicates an old ulcer which has healed in, leav- 
ing a cicatrix. 

The symptoms of keratitis are essentially the same 
in all types. Pain, lacrimation, and photophobia are 
nearly always present. Reflex contraction of the lid 
(blepharospasm) is a common symptom, except in those 
cases caused by paralysis of the fifth and seventh nerves. 
In the former case there is no pain. 

Keratitis is divided into two principal types— the 



90 OPHTHALMOLOGY FOR VETERINARIANS 

suppurative and the non-suppurative. The suppurative 
includes all ulcers, and those forms which are induced 
by infection from without. The non-suppurative type 
includes pannus, the vesicular and punctate forms, 
interstitial and all forms of keratitis, which are, as a 
rule, caused by constitutional disease. 

Ulcer of the Cornea. — As the cornea is the most ex- 
posed portion of the eye, an ulcer is one of its most com- 
mon affections. Ulcers range in degree from the sim- 
plest form, minute in size, to the destruction of a large 
area of corneal tissue, and their course is influenced, to a 
great degree, by the' organism causing the ulcer, its 
early treatment, and the constitutional resistance. 

Simple ulcers begin with a small infiltration, which 
eventually breaks down. They are usually clean, though 
they may have a slight grayish base. They may be ir- 
regular in shape, though usually circular. They have, 
under proper treatment, a tendency to heal readily 
without advancing. 

In severe types the inflammation extends backward 
into the deep structures or spreads over a large area in 
the anterior layers. Deep ulceration may invade the 
whole thickness of the cornea. When perforation takes 
place there is a loss of aqueous with a prolapse of the 
iris into the wound. This remains impacted, and be- 
comes adherent at the point of prolapse. At this stage 
resolution usually begins, and there is a gradual filling 
in or restoration of tissue, later marked by the presence 



DISEASES OF THE CORNEA 91 

of a cicatrix or scar, which is opaque. If the perforation 
is not over the pupillary area it does not materially in- 
terfere with vision except by traction upon the iris 
over the point of prolapse, which causes a dislocated 
pupil to the point of prolapse or adhesion. If per- 
foration occurs over the pupillary area a permanent 
fistula may be the result, or the anterior capsule of the 
lens may be drawn into the wound and an adhesion 
takes place. An opacity' then occurs at this point which 
interferes with vision very greatly, as it is directly in the 
central field. 

Causes. — Traumatism is the most common cause, 
such as the presence of a foreign body or the careless 
removal of one, followed by infection; scratching the 
cornea by a twig or whip; a misdirected eyelash; a burn, 
or an injury which breaks the epithelium and carries 
infection with it, or later becomes infected. Infection 
is the ultimate cause of all corneal ulcers. When free 
from infection much mechanical injury of the cornea 
may be done without purulent inflammation following. 
Exposure keratitis, followed by ulceration, may be 
primarily caused by lagophthalmus, exophthalmus, and 
paralysis of the fifth nerve. Purulent diseases of the 
conjunctiva and lacrimal apparatus, cow-pox, in- 
fluenza, and other infectious diseases are common 
causes. The streptococcus, staphylococcus, pneumo- 
coccus, and other pyogenic bacteria are the infecting 
agents. 



92 OPHTHALMOLOGY FOR VETERINARIANS 

Some types of ulcers are more severe than others; 
they have special characteristics and are known by 
special terms. 

The crescentic ulcer occurs near the limbus or sclero- 
corneal margin, and from its location is also known as 
marginal keratitis. It begins as an interrupted line of 
infiltration beneath the epithelium. Small pustules arise 
along its course, which coalesce. The epithelium soon 
breaks down and a continuous ulcer results. As a rule 
it is confined to the superficial layers and may spread to 
the center of the cornea, leaving in its wake a thin cica- 
trix. It may terminate favorably in a few days, though 
its progress is often protracted, and months may elapse 
before recovery takes place. It most frequently occurs 
in the aged. 

The Serpiginous Ulcer. — This is one of the most 
destructive types of sloughing ulcer. It is character- 
ized by a grayish-yellow disk-like patch, centrally 
located, with an opacity about the border and somewhat 
elevated. Numerous radiating striae invade the corneal 
surface; the anterior layers break down and eventually 
a large ulcerated area filled with pus results. There is 
usually much pain connected with it in and about the 
eye, though in some cases the pain is not so intense as 
the pathologic process would lead one to believe it 
might be. Iritis and iridocyclitis with hypopyon very 
frequently occur. In many cases the ulcer perforates 
the cornea, allowing the escape of aqueous and pus. 



DISEASES OF THE CORNEA 93 

The pus in the anterior chamber does not come from the 
cornea, but from the inflamed condition of the struc- 
tures within the globe. When perforation takes place 
the severity of the central portion subsides, though 
destruction of the tissue may proceed along the borders 
until the whole cornea has become destroyed. Per- 
foration is followed with a prolapse of the posterior struc- 
tures; the iris falls into the opening, or, if exactly central, 
the lens capsule may fill the perforation and become 
adherent. After perforation, healing takes place much 
more quickly, though there is a scar left which is 
opaque and interferes with vision. In extremely severe 
types purulent inflammation of the uveal tract occurs, 
the eye is lost, and shrinking of the globe follows. 

A purulent ulcer is any ulcer which rapidly or slowly 
sloughs. It is due to the entrance of pyogenic bacteria 
following an injury to the cornea. The progress invades 
the deep corneal layers at the point of commencement 
and a rapid destruction of the tissue follows. Early 
treatment should be employed in order to save the eye. 

Hypopyon is pus in the anterior chamber. It gravi- 
tates to the lowest portion of the chamber; and if fluid 
in character it changes its position upon movements 
of the head. 

Treatment of Corneal Ulcers. — The treatment of all 
ulcers of the cornea must be prompt, and energetic 
measures employed. If the ulcer is a small one and 
apparently clean, simple antiseptic washes may be used, 



94 ' OPHTHALMOLOGY FOR VETERINARIANS 

followed by the yellow oxid of mercury ointment to 
promote healing. One of the best mild antiseptic washes 
is the saturated solution of boric acid with a little 
astringent added. Zinc sulphate is usually employed 
for this purpose in the strength of \ to i grain to the 
ounce. 

If the ulcer is a foul one, that is, filled with purulent 
matter, the object in treatment is to kill the bacteria 
causing it, and at the same time to prevent its advance- 
ment. Cureting the ulcer to the healthy tissue was 
formerly employed, and in some cases is a valuable pro- 
cedure if done by experienced hands; but much care must 
be used, or more damage than good will be done by the 
use of the curet. One of the best cleansing agents is one 
of the new silver salts, either argyrol or protargol, from 
10 to 50 per cent, solution. It is well to use the stronger 
solution at first, gradually reducing the strength as one 
gets results. This should be dropped into the eye, 
and soon washed away with the purulent matter which 
the silver salt has coagulated. This operation can be 
repeated every one, two, or three hours, according to the 
severity of the case; between times wash the eye freely 
and frequently with a saturated solution of boric acid. 

If the ulcer does not respond to this treatment, but 
rather increases in size and depth, touch it slightly with 
the strong tincture of iodin. As this is exceedingly pain- 
ful, it should be preceded by the application of a 5 to 10 
per cent; solution of cocain dropped on the cornea. 



DISEASES OF THE CORNEA 95 

Sharpen a matchstick or wooden toothpick, wind a small 
piece of cotton on this so that it will point sharply 
beyond the point of the stick, dip it in the iodin tincture, 
but do not have so much on the cotton that it will drop 
or run. Hold the lids well open, and paint the surface 
of the ulcer, using care that none touch the other por- 
tions of the cornea. Keep the lids open a short time 
until the alcohol has evaporated. This operation may 
be repeated every two or three days if necessary. Most 
admirable results have followed this method of treat- 
ment. The writer has used iodin- vasogen in place of the 
tincture of iodin in some cases with good results. 

In place of the iodin, or in conjunction with it, after 
the immediate irritation has subsided, powders may be 
dusted into the eye. Iodoform is one of the best, either 
in full strength or mixed with equal parts of fine boric 
acid. This fills the ulcer, destroys bacteria, absorbs 
secretion, and has, to some extent, an anesthetic effect. 
When powders are used in the eye, the finest quality, 
free from lumps and foreign matter, should be selected. 
They may be used in a powder-blower or, better, dip 
a camels' haif brush into the fine powder, hold it in front 
of the eye between the thumb and second finger, and 
give it a quick strike with the index-finger, which will 
cause the powder to fly into the eye. Aristol and 
calomel are sometimes used in these cases. 

Antiseptic and stimulating ointments are of much 
benefit after the sloughing process has subsided. Among 



96 OPHTHALMOLOGY FOR VETERINARIANS 

the best of these are the yellow oxid of mercury ointment, 
4 to 8 grains to the ounce, or the red iodid of mercury 
ointment, i grain to the ounce. In all ointments for the 
eye the drug should be well incorporated with the base, 
and ground evenly and smoothly, as the smallest free 
particle of the drug will produce much irritation, the 
same as a foreign body. Iodoform is often used in the 
form of an ointment in strength of from 2 to 25 per cent. 
The base is often made of vaselin alone, but equal parts 
of vaselin and lanolin are better. In applying the 
ointments, place a piece about the size of a pea on the 
everted lower lid and draw the upper lid over it, after 
which use gentle massage over the closed lids. Oint- 
ments of standard strengths are now put up by supply 
houses in tube containers which are very convenient. 

Heat is always indicated in ulcer of the cornea. This 
is best applied by pieces of cotton wrung out in boiling 
water and placed over the closed lids, as hot as they can 
be borne by the hand. In acute cases this should be done 
every hour or two, and before using other treatment. 

Atropin should always be used if the ulcer is centrally 
located, but if it be near the margin of the cornea a 
myotic is indicated. 

The eye should be protected with a pad, and if the 
ulcer is a deep one a pressure bandage should be used. 

When rupture of the cornea seems inevitable the best 
method is to hasten it by a Saemisch operation. This is 
done by passing the point of a Von Graefe cataract 



DISEASES OF THE CORNEA 97 

knife through the healthy cornea near the margin of the 
ulcer, pass it along horizontally in the anterior chamber, 
and cause the point to emerge through the healthy cornea 
near the opposite margin, cutting forward through the 
ulcer. This can be done under local anesthesia. Atropin 
should be used, so that the iris will not prolapse into the 
wound. This operation at once reduces the tension if 
there be any, and allows the escape of aqueous and pus 
from the anterior chamber. Under slight pressure and 
the continued use of atropin and antiseptics resolution 
sets in more readily. 

When the pneumococcus, which is said to be the cause 
of serpigenous ulcer, is present, the antipneumococcic 
serum has been used with great benefit. 

Pannus — This is an affection of the upper and ante- 
rior layers of the cornea, characterized by an opacity of 
these layers, rilled with numerous ramifying blood-vessels. 

In mild types the affection is superficial to Bowman's 
membrane, but in severe types this membrane is de- 
stroyed and the cornea proper becomes invaded. It is 
due to friction of the diseased conjunctival surface of 
the lid, more particularly to trachoma, and to an ex- 
tension of the pathologic process to the layers of the 
cornea. 

The degree and rapidity of the disease may be so 
great as to involve the whole upper surface of the cornea, 
even encroaching over the pupillary area, and some- 
times covering the whole corneal surface. 



7 



98 OPHTHALMOLOGY FOR VETERINARIANS 

The characteristic radiation of the blood-vessels, its 
location, together with the presence of trachoma, serve 
to distinguish it from other diseases of the cornea. 

When the lids are contracted and the palpebral 
fissure is lessened in consequence, the greater is the 
liability of its occurrence. The superficial type readily 
clears up under proper treatment, but the longer the 
disease prevails and the deeper the structures involved, 
the more certain will there be a permanent opacity. 

Treatment. — The main indications are to relieve the 
pressure of the lids upon the cornea, and to treat the 
trachomatous disease of the conjunctiva as described 
under that head. The pressure can be . relieved by 
dividing the outer tendon of the orbicularis muscle as 
follows: Pass the blunt end of the blade of a strong 
pair of scissors horizontally beneath the outer canthus, 
the other above, make one quick snip; at the same time 
keep the parts stretched with the thumb and forefinger 
of the other hand. If the result is unsatisfactory, 
divide the remaining strands with a small pair of scissors. 
Bleeding can easily be stopped by compression, and the 
wound heals rapidly. This operation is known as 
canthotomy. 

If one desires to draw the wound together to obtain 
a permanent result, three sutures may be introduced 
horizontally, one through the conjunctiva to the ex- 
treme angle of the wound, the remaining two, one 
above and one below, at a point midway between the 



DISEASES OF THE CORNEA 99 

first suture and the upper and lower inner angles of the 
wound, avoiding the deep structures. This operation 
is known as canthoplasty. 

The red iodid of mercury ointment, 1 grain to the 
ounce, with a 1 per cent, solution of atropin, applied 
three times a day, is of great value, together with general 
cleanliness and the treatment of the lids. 

If much opacity of the cornea remain, treatment as 
described under that head may be employed. 

Phlyctenular Keratitis. — This is a vascular disease, 
and may appear on any portion of the corneal surface, 
but is more often seen at the limbus and associated 
with phlyctenular conjunctivitis, under which head it is 
described. 

Herpes Corneae.— This is a form of vesicular keratitis. 
It usually occurs in conjunction with herpes on other 
portions of the body or face, such as the lips, nose, 
forehead, and eyelids, more especially when these 
eruptions accompany or follow febrile diseases of the 
respiratory tract, such as influenza, pneumonia, bronchi- 
tis, etc. It is characterized by a vesicle — one or several — 
which is at first clear, but soon becomes cloudy or yel- 
lowish in color, eventually breaks down, and forms a cor- 
neal ulcer. Much pain and irritation attend it. The 
prognosis is good if carefully treated, but if neglected 
destruction of the cornea may occur by widespread 
ulceration. The treatment is principally symptomatic. 

Herpes zoster also attacks the cornea. It is much 



ioo OPHTHALMOLOGY FOR VETERINARIANS 

like the former, though more severe and protracted in 
its course, and the deep structures are more liable to 
become involved. One special feature is, the cornea is 
insensitive to touch. Holocain, in i per cent, solution, 
dropped on the cornea every two hours, is of great 
value, together with general symptomatic treatment. 

Dentritic Keratitis. — This is a superficial type of 
keratitis characterized by branching processes. The 
branches have the appearance of a grayish elevated line 
of infiltration. The epithelium covering these branches 
soon breaks down, forming slight furrows. This may 
remain superficial in character, or it may invade the 
deeper structures of the cornea and result in perforation. 
The disease is said to be due to malaria, though it 
occurs frequently quite independent of malarial in- 
fluence. 

Treatment. — When malaria exists it should be properly 
treated. Dumb animals as well as man have this dis- 
ease. Antiseptic washes and stimulating ointments, 
together with general treatment, is all that can be 
recommended. The disease is often very protracted in 
its course and seems to resist all treatment. 

Filamentous Keratitis. — This is characterized by a 
mass of twisted thread-like growths from the corneal 
surface. They are composed of epithelial cells, which 
become elongated and have the appearance of fibrillae. 
They often arise from the floor of an ulcer or from an 
abrasion of the epithelium. The number of the fila- 



DISEASES OF THE CORNEA 101 

ments may be few or numerous. They undergo mucoid 
degeneration, and after one crop disappears, in a few 
days fresh crops appear. 

Treatment—As the disease occurs in debilitated sub- 
jects, tonic treatment as well as local should be used. 
Mild antiseptic and astringent washes and protection 
are sufficient in the majority of cases. 

Desiccation Keratitis.— This is caused by want of 
proper lubrication and protection, by failure of the lid 
to cover the corneal surface, due to paralysis of the 
orbicularis palpebrarum muscle, to extreme exophthal- 
mus or ectropion. The condition is confined to the 
superficial layers, though in neglected cases the deep 
layers become involved, including the iris and ciliary 
body. 

Treatment. —When the muscle is paralyzed, the lids 
can be brought together and retained in that position 
by the aid of adhesive plaster. This affords the natural 
moisture to the cornea, and with proper stimulating 
ointments the advancement of the disease can be 
aborted. In the case of extreme exophthalmus very 
little can be done except to treat the cause of the 
proptosis and apply lubricating ointments and oils to 
prevent the cornea from becoming dry. Ectropion 
must be treated surgically. 

Neuroparalytic Keratitis.— This is much like desicca- 
tion keratitis, except that the former is due to want of 
protection, while the latter is due to insensibility of the 



102 OPHTHALMOLOGY FOR VETERINARIANS 

cornea and adjacent structures by reason of disease of 
the fifth nerve. The cornea is not sensitive to the 
presence of dust and foreign bodies, the reflex secretion 
of the lacrimal gland is interfered with, and the act of 
winking is lessened in frequency; hence the cornea 
becomes dry, the epithelium eroded and subjected to 
the lodgment and growth of destructive bacteria, and 
loss of substance through ulceration is the result. 

Treatment. — The treatment in this condition is 
obvious. Protection of the cornea is the principal 
indication, with the continuous use of antiseptic oint- 
ments. If ulceration has taken place the general treat- 
ment of ulcers and protection must be employed. The 
cause of the diseased nerve must also be looked for and 
treated. 

Keratomalacia or Xerosis of the Cornea. — This is due 
to dryness of the cornea in conjunction with xerosis of 
the conjunctiva, under which head it is described. 

Staphyloma of the Cornea. — This is a protuberance 
of the cornea produced by ulceration, perforation, and 
prolapse of the iris. It may be partial or complete; and 
in shape conic or hemispheric. The spheric form is 
more frequent, and includes a general bulging of the 
cornea, forming a sharp outline from the scleral margin. 
The wall of the staphyloma becomes very thin in places, 
showing the iris pigment, giving it the appearance of a 
bluish grape. In other instances the wall is thick and 
appears white or opalescent. Numerous blood-vessels 



DISEASES OF THE CORNEA 103 

may be seen radiating over the surface. Cicatricial 
bands form over the point of perforation, causing a 
special thickening of the wall at that point. The anterior 
chamber becomes obliterated, as the iris is closely ad- 
herent to the posterior portion of the cornea. 




Fig. 23.— Staphyloma of the cornea of the human eye. Prepared by 
the author. This condition was due to trachoma. Tc the right of the 
center of the cornea is the point of ulceration and perforation, with exu- 
dation and thickening. To the left the iris can be seen glued to the 
cornea, which is extremely thin. The light spot in the center is a bubble. 

A partial staphyloma is confined to one portion of the 
cornea, is cone shaped, and has a white apex. The 
remainder of the cornea is clear. The iris is only ad- 
herent at the point of perforation. This usually pro- 
duces dislocation of the pupil, and, with the irregularity 
of the corneal curvature, interferes with vision. 

Treatment. — As ulceration of the cornea is the primary 



104 OPHTHALMOLOGY FOR VETERINARIANS 

cause of staphyloma, this should be treated according 
to the rules under that head. If the perforation occurs, 
a bandage should be applied with moderate compres- 
sion, the bowels kept open, and any undue exertion pre- 
vented. When the staphyloma is complete the eye is 
of no practical value, though light may be perceived. 

If tension is present in the early stages a small inci- 
sion through the cornea, at its margin, may be made, 
which allows the escape of the aqueous, reduces the ten- 
sion, and encourages the reduction of the thin wall. 
The eye should then be protected with a bandage with 
gentle pressure. When the eye has lost its function by 
reason of extreme staphyloma an operation may be 
performed for cosmetic purposes, as the condition is 
very unsightly; also to allow the lids to cover the globe 
more completely. The operation according to the 
method of De Wecker, known as ablation or excision, 
may be employed. The conjunctiva is first divided 
around the limbus, undermining it some distance from 
the margin, threads are then passed through the upper 
and lower portion of this tissue, so that it may be 
drawn together much like the mouth of a tobacco 
pouch. The staphyloma is then abscised, beginning 
at the lower margin with a cataract knife and finishing 
with curved scissors. Through the upper and lower 
margins stitches are placed for the purpose of drawing 
it together, but before doing this the lens is removed 
after incising its capsule. The corneal sutures are then 



DISEASES OF THE CORNEA 105 

drawn tightly and tied, and the whole covered by the 
conjunctiva by tightening and tying the puckering 
threads. The excision should be performed so as to get 
a transverse closure and as near the center as possible, 
to avoid irritation in the act of winking. 

Keratectasia is a protrusion of the cornea following 
a keratitis without perforation, though the cornea has 
become thin by destruction of the superficial layers 
and offers little resistance to intra-ocular pressure. 
It differs from a staphyloma in that the iris is not 
involved. 

An incision through the cornea at the margin, followed 
by a compress bandage, is of value, though if tension 
persists an iridectomy should be done, not to reduce the 
tension alone, but for visual purposes as well. 

Keratoconus, or conic cornea, resembles keratecta- 
sia in some respects. It is not due to an inflammatory 
process, however, and does not become opacified. It 
is caused by a thinness of the corneal layers which 
yield readily to the pressure within the globe, causing 
the cornea to assume a clear cone shape. 

Keratoglobus, also called hydrophthalmus and buph- 
thalmus (ox eye).— In this case there is not a protru- 
sion of the cornea alone, as in the preceding diseases, 
but rather an enlargement of the cornea in keeping 
with the general enlargement of the globe. It is con- 
genital, as a rule, or appears in early life, and is said 
tc be analogous to glaucoma in later fife. The coats 



106 OPHTHALMOLOGY FOR VETERINARIANS 

of the globe are thin, and the pigment can be seen 
through the sclera, giving it a bluish appearance. The 
tension is increased, and when this subsides the dis- 
ease ceases; but, if the tension continues, the disease goes 
on to ultimate blindness. Both eyes are affected. It 




Fig. 24. — An extreme exophthalmos or protrusion of the globes, 
more marked in the left, due to an abnormal fatty growth in the orbits. 
Notice the opacity of the cornea from exposure. 

is said to be hereditary, though the exact nature and 
cause of the disease is not fully understood. 

Opacities of the Cornea. — Opacities are the result of 
ulceration or disease of the true corneal layer. They 
may be small or large, thin or opaque, according to the 
extent and depth of the disease. 

Opacities are usually divided into three degrees: 



DISEASES OF THE CORNEA ' 107 

first, a nebula, which is a slightly clouded patch ; second, 
a macula, a somewhat denser patch; and third, a leu- 
koma, a dense opalescent patch. 

If the opacity is not over the pupillary area it does 
not materially interfere with the vision, but if it be 
centrally located vision of the central field is de- 
stroyed. 

Treatment. — As the opacity is composed of cicatricial 
tissue quite different in structure from the normal 
elements of the cornea, it is impossible to reproduce a 
perfect transparency, though in some cases the results 
are surprising when proper treatment is employed. 
The following remedies are useful: Dionin, in solution 
of 5 to 10 per cent., or in the form of the powder, is 
probably the best. Begin with 5 per cent, solution and 
drop into the eye three to five times a day. This at first 
produces an extreme reaction, and causes the con- 
junctiva to become very red and edematous. When this 
takes place, use it less frequently. The reaction subsides 
in a day or two, and, after using the dionin a few times, 
it ceases to have this effect, when a stronger solution 
may be employed. In conjunction with this use the 
yellow oxid of mercury ointment in the eye three times 
a day, followed by massage. An ointment of thiosinamin, 
10 per cent., is also recommended. The results are due, 
in great part, to massage used with the applications. 
Massage alone has been followed with excellent results. 
One must have patience in the treatment of opacities, as 



108 OPHTHALMOLOGY FOR VETERINARIANS 

it takes a long time to accomplish any degree of clear- 
ness. When the opacity is centrally located, and it 
cannot be made clear by medication, an iridectomy may 
be done for optical effect. 

Interstitial Keratitis. — This is also known as paren- 
chymatous keratitis, keratitis profunda, and keratitis 
diffusa. 

It is essentially a disease of the young, and the usual 
cause in man is hereditary syphilis, though it frequently 
occurs in dogs as a result of distemper. It may begin at 
the center or margin of the cornea, as a grayish macula 
located in the stroma. This gradually extends until 
the whole cornea becomes invaded, and the tissues 
become opaque and assume a ground-glass appearance. 
On close inspection vessels may be seen ramifying 
through the deep layers, while some have tuft-like 
branches near the margin. The disease is very pro- 
tracted in its course, and one or more months may 
elapse before it has reached its height, when the severity 
of the symptoms will gradually subside, and it may 
then require months before the cornea will resume its 
normal transparency; and there is a probability that it 
will never become transparent again. In some cases 
the disease is more localized and confined to small 
areas. As a rule the vascular condition exists in pro- 
portion to the extent and degree of infiltration. There 
are non- vascular forms, however, in which very few 
vessels can be seen. Being confined to the stroma, 



DISEASES OF THE CORNEA 109 

ulceration does not occur, nor does- purulent disintegra- 
tion follow, as in the superficial types of keratitis. 

The general symptoms of keratitis accompany the 
interstitial type— viz., pain, lacrimation, and photo- 
phobia. In severe cases iritis and inflammation of 
other portions of the uveal tract occur. The fellow eye 
becomes involved sooner or later, and when syphilis is 
the cause the knee-joints may become swollen and 
tender to pressure. 

Treatment.— When caused by specific disease, consti- 
tutional treatment must be employed. Locally, relieve 
the eye of any undue irritation from strong light, etc. 
Atropin should be employed to give the accommodation 
rest and relieve or counteract a possible attack of iritis. 
Should iritis arise, dionin may be used in conjunction 
with atropin, and later the yellow oxid of mercury 
ointment added to this treatment, to promote absorp- 
tion and assist in clearing the cornea of remaining 
opacities. Should conjunctivitis exist, as it often does 
in the case of distemper, this should be treated on gen- 
eral principles. 



CHAPTER IX 
DISEASES OF THE IRIS AND CILIARY BODY 

The structure of the iris is practically the same in all 
animals, though the arrangement of the muscle-fibers 
differ somewhat. For example, the pupil of the horse 
is elliptic horizontally, while that of the cat has the 
appearance of a vertical slit during contraction. The 
corpus nigra, suspended from the upper portion of the 
horse's pupil, has the appearance of a pathologic tumor. 

The color depends upon the amount of pigment 

present in the posterior layers and in the meshes. Some 

animals — white rabbits for instance — are devoid of 

pigment and the irides are of a pinkish color. In horses 

this is occasionally seen as a partial defect, a portion 

only of the iris and adjacent structure appearing white 

or pink. It is not unusual in the human family to see 

persons with little or no pigment in the irides, and when 

such is the case the hair and other portions of the body 

are lacking in this element. Such persons are known as 

"albinos." An unequal amount of pigment in each 

iris causes one to look blue and the other brown or 

black. 

no 



DISEASES OF THE IRIS AND CILIARY BODY in 

Congenital defects of the pupil are often noticed, and 
one of the most common is a persistent pupillary mem- 
brane. It is common in man, and has been seen in the 
horse, ox, dog, and rabbit. Youatt mentions a case 
of congenital blindness from this cause in a female 
pointer eight weeks old (Steel's "Diseases of the Dog"). 
"Meyer notes the case of a congenital double pupil 
in a horse; a bridge extending across the space from the 
upper to the lower border, and cutting off the outer 
third of the opening" (Law's "Veterinary Medicine"). 
Ectopia pupillce, or displacement of the pupil, is not 
uncommon, and frequently accompanies luxation of the 
lens. Coloboma of the iris is a condition in which a por- 
tion of the iris is absent from the border of the pupil 
to the periphery, causing a large, irregular opening. 
Aniridia is a condition in which the iris is absent. 
These congenital defects should not be confounded with 
pathologic conditions following iritis, injuries, etc. 

The size and shape of the pupil vary in different 
animals, and are influenced by light, darkness, ac- 
commodation, medication, and disease. 

Mydriasis, or dilatation of the pupil, is due to paralysis 
of the third nerve, irritation of the ciliospinal center, 
constitutional diseases, diseases of the central nervous 
system, contusions, intra-ocular pressure, and certain 
drugs known as mydriatics. 

Myosis, or contraction of the pupil, is caused by 
paralysis of the cervical sympathetic, tabes dorsalis, 



112 OPHTHALMOLOGY FOR VETERINARIANS 

inflammation of the iris, foreign bodies on or in the cor- 
nea, and certain drugs known as myotics. 

W. B. Coakley 1 has noted pin-point contraction of the 
pupil as a pathognomonic eye-symptom in rabies. 
"The contraction is so strong as to resist the effect of 
mydriatics." He further says, "A contracted pupil 
which yields to mydriatics is sufficient to exclude 
hydrophobia. There is medium dilation immediately 
before death." In the same article he notes that "alco- 
hol, opium, morphin, codein, carbolic acid, eserin, and 
chloral, all of which contract the human pupil, were 
given to dogs in lethal doses without producing the 
myosis noted in rabbits." 

- Iritis, or inflammation of the iris. The iris is practically 
an extension of the anterior portion of the ciliary body, 
and we will consider them together. The relation of the 
blood-vessels and their source must be kept in mind, 
as those of the chorioid ciliary body and iris are inti- 
mately associated, and a knowledge of their arrangement 
is necessary when we come to consider inflammation of 
these structures, as it is rather exceptional for the iris 
to be inflamed when the ciliary body is not more or less 
involved. 

An iritis may be mild or severe in type. The iris be- 
comes hyperemic, the blood-vessels dilated, and a 
change of color from that of the other iris takes place, 
according to the amount of inflammation present. 
1 Medical Record, July 6, 1907. 



DISEASES OF THE IRIS AND CILIARY BODY 113 

This change of color is not as marked in dark-colored 
irides as in those of a lighter color. A bluish iris be- 
comes greenish in color. The iris loses its luster and its 
fine lines are less distinct. If this hyperemic condition 
goes on to a more severe type of inflammation, exuda- 
tion occurs and the iris becomes muddy in appearance. 
This exudation is composed of leukocytes and other 
inflammatory debris which settle to the bottom of the 
anterior chamber, where it may be seen as a whitish line, 
and varies from one barely visible to one filling the cham- 
ber. The more of this exudate there is present, the more 
clouded the iris appears. Not infrequently the blood- 
vessels rupture, and the blood settles in the most de- 
pendent portion of the anterior chamber, as does the 
exudate. Blood in the anterior chamber is called 
hyphemia. The exudate is often deposited on the 
posterior surface of the cornea and the anterior surface 
of the lens' capsule, which produces a grayish appear- 
ance to the pupillary area. It sometimes undergoes a 
fibrinous change, and the pupillary area is occluded by 
an apparent membranous formation. 

In types of a mild, slow, chronic nature, and more 
particularly when the uveal tract is involved, the 
exudate may be seen by the aid of a strong lens de- 
posited, as pin-point dots or larger, on the posterior 
layer, even when, to the unaided eye, it may appear 
clear. This precipitates to the bottom of the anterior 
chamber and forms a pyramid mass. That thrown out 



114 OPHTHALMOLOGY FOR VETERINARIANS 

from the posterior pupillary border assists in cementing 
the border of the pupil to the anterior capsule of the 
lens, either partially or completely. These adhesions 
are called posterior synechia?. When the iris is com- 
pletely adherent it is known as seclusion of the pupil; 
when this occurs, together with the formation of a mem- 
brane over the pupillary area, it is called occlusion of the 
pupil. When this takes place the eye becomes blind. 
Occluded pupil has frequently been found in the horse 
as a sequel of iritis. 

An iritis and a cyclitis — iridocyclitis — often occur at 
the same time; however, an inflammation of one or the 
other of these bodies may be more pronounced. 

Cyclitis is nearly always accompanied by tenderness 
over the ciliary region, and the congestion is more 
marked over this locality. According to Law, "it occurs 
in domestic animals, as described by Moller, but he fails 
to furnish instances of its diagnosis during life, and it is 
not likely to be recognized in living animals. Besides the 
usual signs of iritis, there is extreme tenderness on 
pressure around the anterior border of the sclera — it 
is quite likely to be complicated by suppuration and to 
go on to panophthalmitis." 

Symptoms of Iritis. — Iritis is accompanied by pain, 
redness of the conjunctiva, small pupil, which reacts 
very sluggishly or not at all, discoloration of the iris, 
and the formation of synechise, which are more notice- 
able when a mydriatic is used. The tension is normal 



DISEASES OF THE IRIS AND CILIARY BODY 115 

unless secondary glaucoma (see Glaucoma) arises. 
Although pain is a symptom of iritis, it is not present in 
all cases, and the presence of iritis in some cases can 
only be determined by the use of the ophthalmoscope, 
when, after the use of a mydriatic, small pigment spots 
may be seen upon the capsule of the lens, near the 
pupillary margin, at the point where the iris has be- 
come agglutinated. 

In the severe types the pain is almost unbearable, 
more intense at night, and it often radiates to the back 
of the head. The conjunctival injection is also very 
great, and if one is not on his guard he may mistake it for 
a conjunctivitis by "snap diagnosis." The course may 
be from one to several weeks. It frequently clears up, 
but may recur in the same or fellow eye. 

Secondary iritis and cyclitis is the result of disease of 
the neighboring structures or injury. The injuries re- 
ceived by penetrating bodies in this region are the most 
apprehensive, more particularly if the penetrating agent 
is not sterile. Wounds of the ciliary region by infected 
bodies produce terrific reaction, as a rule often fol- 
lowed by loss of vision and suppuration of the uveal 
tract. 

One of the gravest consequences of this "condition is 
sympathetic involvement of the other eye — sympathetic 
ophthalmia— manifest at first by irritation, and later 
by inflammation of the iridociliary region, and eventu- 
ally loss of that eye also. So that it behooves us to ex- 



n6 OPHTHALMOLOGY FOR VETERINARIANS 

ercise the utmost caution, judgment, and care in our 
treatment of the primary cause. 

Just how sympathetic inflammation is brought about 
no one seems to know definitely, but it is presumed to be 
effected through the lymphatic vessels or the circulatory 
system. Many a person has become blind in both eyes, 
which might have been otherwise had the injured eye 
been sacrificed in due season. 

Whether the object remains in the eye or not, or 
whether this region has been simply pierced by a dirty 
instrument, the result is the same as a rule. No longer 
than six days should elapse before removing the offend- 
ing eye, otherwise the fellow eye may become affected. 

The iridociliary region is involved in all cases of recur- 
rent ophthalmia of animals, and it is not uncommon to 
see the fellow eye follow in its wake; but, until we know 
more definitely what the exact cause is of recurrent 
ophthalmia, we are at sea as to the best method to 
pursue in preventing sympathetic involvement, as the 
cause in the second eye may be the same as in the first, 
and not sympathetic, as we understand sympathetic 
ophthalmia. 

Treatment of Iritis and Cyclitis. — The treatment is 
constitutional and local. The cause should be sought 
and that treated. Influenza, tuberculosis, rheumatism, 
and other forms of infectious diseases are often the 
cause, and appropriate treatment is called for. Keep 
the animal quiet, in a dark stall, where it may be free 



DISEASES OF THE IRIS AND CILIARY BODY 117 

from the irritating effects of light, dust, dampness, etc. 
Open the bowels freely and keep them open, to relieve 
it from the absorption of toxins. See that the animal 
is kept under the best hygienic conditions. In debili- 
tated subjects, tone up the system by the administration 
of suitable tonics. 

Local treatment consists in preventing the formation 
of synechias, relieving pain, rest of the accommodation, 
depletion, absorption of inflammatory products, etc. 

Atropin in solution is one of our best remedies in 
iritis. It paralyzes the accommodation, lessens the 
congestion, dilates the pupil, thereby preventing the 
formation of adhesions of the pupillary margin, and 
assists in relieving pain. In man it is used in 1 per cent, 
solution, but the solution must be graduated in strength 
according to the size and weight of the animal. The 
frequency of the application will depend largely upon 
the case. Usually three times a day is sufficient. 

Dionin is one of the newer remedies, and, in conjunc- 
tion with atropin, one of the best. It relieves pain and 
promotes activity of the lymphatic circulation. It 
acts better following the application of moist heat. 

Heat, properly applied, is almost indispensable. A 
cloth or wad of absorbent cotton may be wrung out of 
boiling water, as dry as possible, and, when it can be 
borne, placed over the closed lids. This should be 
repeated every minute for six or eight times every hour. 
The eye should never be poulticed. 



n8 OPHTHALMOLOGY FOR VETERINARIANS 

In cases of iridocyclitis, when the inflammation of the 
ciliary body is more pronounced, and in cyclitis pure and 
simple, atropin should be used with caution, as in many 
cases it is not well borne; besides, when this agent is 
used, the tension should be closely watched. Should 
any increase of tension occur the atropin should be 
immediately stopped and a myotic employed. 

In severe cases of inflammation and congestion 
several leeches may be applied over the region of the 
temple. They assist greatly in reducing the inflamma- 
tory symptoms. 

Operative measures should not be employed during the 
active stage of inflammation as a rule. Iridectomy 
may be done when the tension becomes increased, and it 
cannot be reduced by less radical means. When the 
pupil becomes secluded or occluded, iridectomy aids in 
re-establishing the natural drainage, and prevents, in a 
degree, subsequent attacks. 

When tension develops, a paracentesis may be per- 
formed. It allows the escape of the aqueous, together 
with inflammatory debris, and assists in reducing the 
tension. 

Enucleation should only be considered in infected 
traumatic cases when the fellow eye is in danger of 
sympathetic inflammation, and in cases accompanied or 
followed by suppuration of the internal structures, or 
when panophthahnitis exists, and the animal's life is 



DISEASES OF THE IRIS AND CILIARY BODY 119 

endangered by extension of the septic elements to the 
meninges. 

Cysts and Tumors of the Iris. — Cysts of the iris are 
rare, though they sometimes appear in the stroma of the 
iris as the result of injury. They are usually very 
gradual in their development. Meyer (in Law's "Veter- 
inary Medicine") speaks of these lesions in horses, 
" but they are very difficult to diagnose even with the aid 




Fig. 25. — Photograph of carcinoma or the orbit of a dog. (Veter- 
inary Record, vol. xvii, p. 694, " Proceedings of the Central Veter- 
inary Medical Society.") 

of the ophthalmoscope. The very manifest bulging at 
the part may be due to excess of pigment, especially in 
the corpora nigra, and an exploratory puncture would 
only be warranted when the protrusion becomes excessive 
and injurious. One such puncture by Eversbusch led 
to infection and loss of the eye." In this instance prob- 
ably the puncture was not made under the strictest 
aseptic precautions. The treatment of cyst of the iris 



120 



OPHTHALMOLOGY FOR VETERINARIANS 



is incision of the cyst at the corneal margin with a 
proper knife-needle. Of course, the same aseptic 
precautions must be observed as in all operative pro- 
cedures. 

Tuberculosis of the Iris. — This has occurred as a result 
of general infection in the smaller animals, and as a. 




Fig. 26. — Photograph of carcinoma of the orbit of a cat. (Veter- 
inary Record, vol. xvii, p. 694, " Proceedings of the Central Veter- 
inary Medical Society.") 



spontaneous localization of disease in cattle. In Hess' 
case "the left eye was shrunken to half the size of the 
sound eye, and the small caseated nodules were present 
in both iris and chorioid." There are usually co-existing 
tubercles in other organs, and these, together with the 
nodular swellings of the iris, may assist in the diagnosis. 



DISEASES OF THE IRIS AND CILIARY BODY 12 1 

" Animals in which the eyes have been experimented on 
by inoculation die of general tuberculosis due to infec- 
tion starting from the eye" (Duane). 

Tumors of the iris and ciliary body are benign and 
malignant. The corpora nigra, which is normal, of 
course, is an example of the so-called melanomata which 




Fig. 27. — Sarcoma of the left orbit. (Dr. Geo. H. Robberts' case.) 

occur in the iris. It springs from the pigment layer at 
the margin of the pupil. Another form is an excess of 
pigment springing from the iris stroma and projecting 
into the anterior chamber. They develop to a certain 
size and may remain stationary. Portions of the pig- 
ment mass may become loose from the main body and 
fall into the anterior chamber. They are benign in 



122 OPHTHALMOLOGY FOR VETERINARIANS 

character, but must produce more or less irritation of the 
iris in its movements of contraction and dilatation. 

Sarcoma sometimes makes its appearance inde- 
pendently in the ciliary body and iris, but is more often 
extended to these portions from primary affection of the 



Fig. 28. — The contents of the left orbit in Fig. 24, cut in the center 
from above downward; a, the eyeball; b, the retractor muscle; c, the 
normal tissue; d, the tumor mass. 

chorioid or the anterior portion of the eye. It is pig- 
mented (melanotic), and when it is confined to the 
ciliary body it cannot be seen or discovered until it has 
reached a sufficient size, as the ciliary region is always 
difficult to see with the ophthalmoscope because it is 
located so far anteriorly. Its location may be deter- 



DISEASES OF THE IRIS AND CILIARY BODY 123 

mined with the transilluminator. This tumor is sooner 
or later destructive to the eyeball and possibly to life. 




Fig. 29— Melanosarcoma of the human eye. Prepared by the 
author. Notice the detachment and folding of the retina and the 
arched condition of the posterior portion of the lens which is pushed for- 
ward to the cornea, practically gluing the iris to it. This is due to the 
extreme intra-ocular tension. 



The only thing to do is to enucleate the eye as soon as it 
is discovered. 



CHAPTER X 

DISEASES OF THE RETINA AND CHORIOID 

Diseases of these coats and also of the optic nerve 
are diagnosed by the use of the ophthalmoscope. This 
instrument is devised for throwing reflected light into 
the eye from a tilting mirror in front of a series of spheric 
lenses; a hole is in the center of the mirror, and the 
small lenses are protected by a circular revolving disk. 
Two methods of examination are used: The direct 
method, by which the physician looks directly through 
the hole in the mirror, the same being close to the 
animal's eye. The light (a candle is sufficient) is placed 
to the right of the animal's head if the right eye is to 
be examined, the ophthalmoscope being held in the right 
hand, and the examiner uses his right eye. In examining 
the left eye, hold the instrument in the left hand, and 
look through the hole in the mirror with the left eye. 
The light should be on the left side of the animal's 
head. When examining either eye the mirror is brought 
close to the eye of the animal, and so tilted as to produce 
a red reflex, when the fundus will be illuminated. If 
the vessels are seen, but are indistinct, the disk may be 
turned so as to bring out the vessels sharply by either 

124 



DISEASES OF THE RETINA AND CHORIOID 125 

a plus or minus spheric lens. The numbers of the plus 
lenses are usually white, while those of the minus lenses 
are red. The examiner's eyes should both be open, 



Fig. 30. — Loring's ophthalmoscope, with tilting mirror, complete disk 
of lenses from — 1 to — 8 and o to +7, and supplemental quadrant con- 
taining ±0.5 and ±16 D. This affords 66 glasses or combinations from 
-f-23 to — 24 D. 

and the accommodation relaxed, as in viewing objects 
through the microscope. The indirect examination is 
made at a greater distance from the animal's eye, and 



126 OPHTHALMOLOGY FOR VETERINARIANS 

with the addition of a spheric lens of about +16 
diopters. In using this method the disk should be 
turned so that a +3 D. lens shows behind the hole in 
the mirror. Support the 16 D. lens with the thumb and 
index-finger of the right hand (for the left eye, and with 
those of the left hand for the right eye), and allow the 
little finger to rest upon the face near the eye, so as to 
guide the distance between the eye and the lens. The 
examiner will hold the ophthalmoscope close to his own 
eye, and pass the reflected light through the 16 D. lens 
near the animal's eye. This method gives a greater 
field, but a reduced image, and usually brings out the 
retinal vessels and optic disk distinctly, even in cases 
of a high myopia. 

It will be well for the veterinary student to use the 
ophthalmoscope as much as possible in the examination 
of the eyes of various animals, and become acquainted 
with normal fundi. This is the only possible way to be 
able to distinguish a normal from a diseased fundus. 
Examine the human eye also, and study the difference 
in the structure of the coats and the arrangement of the 
vessels from those of dumb animals' eyes. (See Frontis- 
piece.) 

Normal fundi of animals of a kind are the same, 
though they may differ in degree of shade or color 
according to the amount of pigment. Anomalous con- 
ditions (such as coloboma of the chorioid or retina) may 
be mistaken for a pathologic change, but experience in 



DISEASES OF THE RETINA AND CHORIOID 127 

examination will teach one the difference. The tapetum 
lucidum may also be mistaken for a pathologic lesion. 
The brilliancy and varied coloring of this portion of the 
fundus is most interesting. A fowl's fundus distinctly 
differs from a quadruped's. There is a projection into 
the vitreous, known as the "pecten," said by some 
authors to be a projection of the chorioid, and by others 
to be a portion of the retinal circulation. It appears on 
cross-section of the eye to project from the optic nerve. 

The retina, although histologically divided into ten 
layers, may properly be divided into tissues of two 
kinds — a nervous and a supporting tissue. It is said to 
be transparent, which is quite evident in fundi with 
little or no pigment when the outlines of the vessels of the 
chorioid can be seen through it. Its system of blood- 
vessels is particularly its own, as they do not anastomose 
with themselves or other systems of vessels except at the 
papilla, where there is a minute connection between the 
retinal and ciliary vessels. 

The retina is subject to anemia, edema, hyperemia, 
hemorrhages, detachment, inflammation, and atrophy. 

Anemia occurs with general anemia and follows severe 
hemorrhages from other portions of the body. It also 
occurs in compression and embolism of the central 
artery. There is a reduction in the caliber of the vessels 
and the retina is generally pale. 

Edema is the result of traumatism and disease, and is 
due to effusion in' the retinal tissues. It presents a 



128 OPHTHALMOLOGY FOR VETERINARIANS 

cloudy appearance, which may sooner or later clear 
away, leaving retinal change. It usually causes a 
reduction of sight. 

Hyperemia accompanies inflammatory diseases of the 
retina and optic nerve, and, in man, a simple hyperemia 
is often due to eye-strain and excessive light. 

Hemorrhages usually follow injuries, diseases of the 
blood-vessels, retina and chorioid, and sometimes take 
place when inflammation is not present. They occur 
along the course of a vessel and are irregular in outline. 
When they occur in the macular region the animal is 
blind in the central field. Sometimes large hemorrhages 
between the hyaloid membrane and the retina occur, 
which precipitate and form a peculiar shape (subhya- 
loid hemorrhage). When the blood is absorbed, which 
usually takes a long time, pigmented spots or atrophic 
white spots remain over the site. 

Detachment is often due to injuries and diseases, 
which cause a fluid vitreous and loss of support of the 
retinal tissue, or to an accumulation of fluid between the 
retina and chorioid when the former is pushed forward. 
The detachment may be confined to a localized area, 
as it is at first, and may then become total. The visual 
fields are largely disturbed in partial detachment, and 
in total detachment complete blindness will follow. 

Retinitis, or inflammation of the retina, is varied in 
appearance and cause. It is characterized by hyperemia 
and edema, indistinct outlines of the papilla, tortuous 



DISEASES OF THE RETINA AND CHORIOID 129 

veins, and, in many cases, numerous hemorrhages. 
White spots appear scattered about the fundus, due to 
the presence of exudates. These exudates often pass 
into the vitreous, causing opacities in this substance. 
The vision is reduced according to the site and degree 
of the inflammation, which is general, though it may be 
localized. 

The appearance by ophthalmoscopic examination 
often depends upon the cause, though in many cases 
the cause is not easily found. Among the various causes 
are Bright's disease, diabetes, syphilis, diseases of the 
vascular system, and diseases of the blood. 

The characteristic early appearance in Bright's 
disease is a radiation of white spots about the macula 
with occasional hemorrhages, and larger exudates in 
various portions of the retina, together with other lesions 
above described. This form of retinitis frequently 1 
occurs in the bitch during the stage of pregnancy. 

The only way to determine the cause of retinitis is 
to give the animal a thorough physical examination, in- 
cluding a chemic and microscopic examination of the 
urine and blood. 

Atrophy of the retina often occurs as a result of a long 
period of inflammation, or the reduction of its nutrition 

1 There is one particular condition which is not infrequent and should 
not be mistaken as pathologic; this is a series of medullated fibers which 
appear like a white flame extending from the optic nerve upward and 
downward, or in one direction only. In such a case the general symptoms 
of retinitis are absent. 



130 OPHTHALMOLOGY FOR VETERINARIANS 

from embolism or thrombosis of its vessels. The latter 
become very small or obliterated, though the remaining 
portion of the retina may appear normal. 

Rupture of the retina is the result of injuries, princi- 
pally contusions of the eyeball. "Cases of isolated lacera- 
tion of the retina are extremely rare. The retina is much 
harder to tear than the chorioid, since in rupture of the 
latter the retina is generally found to be uninjured" 
(Duane). 

Glioma. — Because of the structure of the retinal tis- 
sue glioma is the only growth the retina is subject to. 
For a long time it has been known as "amaurotic cat's 
eye," from the fact that the eye is blind, and the fundus 
reflex looks like that from the tapetum of the retina of 
the cat's eye in the dark. A glioma is a very malignant 
tumor and occurs in the young. If not early removed, it 
soon extends to the optic nerve and brain and results 
fatally. Besides extending backward, it grows forward 
and laterally into the tissues of the orbit. The globe is 
much enlarged and ugly ulcerations may take place. 
It may attack one or both eyes. It is one of the most 
malignant and fatal diseases of the eye with which we 
have to deal. 

Diseases of the Chorioid 

Because of the close connection with the retina 
these two coats are nearly always affected when one or 
the other is first inflamed. This is known as a retino- 



DISEASES OF THE CHORIOID 131 

chorioiditis; however, diseases of these coats do appear 
to exist independently, and when the chorioid alone is 
inflamed it is called chorioiditis. The distinction is made 
by the retinal vessels, without a break, passing over the 
chorioidal lesion. 

The chorioid is a portion of the uveal tract extending 
forward and including the ciliary body and iris, and 
these bodies are often inflamed in conjunction with the 
chorioid, when it is known as iridochorioiditis. These 
are the parts first affected in recurrent ophthalmia. 

The chorioid is a vascular and pigmentary coat, with 
supporting connective tissue, and is subject to simple 
and inflammatory affections. It rests upon the white 
sclera, and for this reason rupture of the coat can be 
easily seen, as can the crescentic rupture near the 
papilla in cases of high myopia. 

The early stages of chorioiditis are manifest by various 
spots of a yellowish-white color due to exudates, when 
the retinal vessels may be seen passing over them. 
Later, by a proliferation of pigment, these spots appear 
black, particularly about the borders. There is always 
a disturbance of vision, with a sensation of flashes of 
light, with marked scotomata. The causes are syphilis, 
scrofula, tuberculosis, and diseases of the blood. In 
cases of high myopia the chorioid suffers many changes 
by reason of severe stretching. 

According to the location and distribution of the spots 
or lesions, chorioiditis is known as central, disseminated, 



132 OPHTHALMOLOGY FOR VETERINARIANS 

and diffuse. If the macula does not become affected, 
central vision remains good. There is little hope of re- 
storing the chorioid to its normal conditions, as atrophy 
of the affected areas usually follow. 

Purulent chorioiditis is the result of infected wounds, 
ulceration of the cornea, and metastasis in cases of 
pyemia and septicemia. The whole uveal tract is usu- 
ally involved. It may undergo absorption when the 
globe becomes shrunken. Panophthalmitis is a condi- 
tion in which the globe ruptures in its orbital portion, 
affecting the orbital tissues; or purulent inflammation 
may originate in the orbit and perforate the coats of 
the eye. 

In all the forms of optic neuritis, retinitis, and chori- 
oiditis, except the purulent type and those associated 
with iritis, there is no pain and no external evidence of 
the disease. The diseases of the retina and chorioid are 
spoken of by some as "internal ophthalmia," but this 
term is indefinite, except to indicate an inflammation of 
the internal structures of the eye. 



CHAPTER XI 

DISEASES OF THE OPTIC NERVE 

The optic nerve is subject to inflammation at any 
point along its course. When it occurs in the anterior 
portion it may gradually ascend along the trunk, and 
when the initial trouble is along the trunk it may descend 
to the optic disk, and will be followed by atrophy in many 
cases. When the disk is inflamed the retina is nearly al- 
ways involved, when it is known as neuroretinitis. The 
causes are traumatism, inflammation of adjacent struc- 
tures, tumors, hemorrhages, and diseases of the central 
nervous system. A portion of the fibers only may be 
affected, when vision will be partly retained, but if all 
the fibers are involved and atrophy follows, vision will 
be entirely lost. When one eye only is affected the 
cause lies anterior to the optic chiasm. 

Papillitis is an inflammation of the optic nerve head 
or papilla. It is usually bilateral, and is due either to 
pressure upon the nerves or tracts or to effusion within 
the sheaths or fibers. The papillae are edematous and 
swollen, larger than normal, and may be reddish, gray, 
pale, or even white, and the outlines are very indistinct. 
The arteries are small, while the veins are large and 

133 



134 OPHTHALMOLOGY FOR VETERINARIANS 

tortuous. The disk appears "choked," and the tissues 
have a striated appearance from the center outward, 
extending into the retina. Vision may be normal in 
some cases, though a marked decrease in the fields and 
acuity of vision is the rule, and sudden blindness some- 
times occurs. The prognosis is always grave. 

Retrobulbar neuritis is inflammation of the nerve 
within the orbit, posterior to the globe. It is often caused 
by influenza and catarrhal disturbances of the nasal 
passages, involving the sinuses directly adjacent to the 
orbital tissues. It may occur in one or both nerves. 
Total blindness may follow an acute attack, caused by 
severe inflammation of the orbital tissues, though 
in the majority of cases only a varying decrease in the 
visual acuity is the result. The fundus is normal in 
appearance, though atrophy of the nerve-fibers may take 
place and descend to the papilla, when it will gradually 
become white. The prognosis is usually good if the 
cause is removed and the nerve-fibers toned by proper 
medication. 

Toxic amblyopia is due to poisons within the system. 
In man, alcohol and tobacco are the principal causes, 
though lead, arsenic, and various other chemic poisons 
may be the cause. Quinin in large doses has produced it. 
"Anatomic investigations in quinin-poisoning, produced 
experimentally in dogs, shows during the very first 
days a destruction of the ganglion cells of the retina, 
these being primarily attacked by the poison" (Duane). 



DISEASES OF THE OPTIC NERVE 135 

It is manifest by a gradual or rapid reduction in sight. 
The central field is the one involved, and from this fact 
it is possible that the poison may attack the nerve ele- 
ments of the macula first and then recede to the optic 
nerves. Colors are not easily distinguished, especially 
red and green. 

The treatment in such cases is to remove the cause, 
keep the bowels open, and tone up the nerve-rlbers by the 
use of strychnin. 

Atrophy of the optic nerve may be simple or inflam- 
matory. In the former the nerve head becomes gradually 
white, without symptoms of inflammation accompanying 
it. The sight is gradually reduced until there is com- 
plete blindness. The principal causes are affections of 
the brain and tabes dorsalis (sclerosis of the posterior 
columns of the spinal cord). The author once saw a 
case of this kind in a cat in which both optic nerves 
were entirely atrophied, with sight and locomotion 
abolished. 

Inflammatory atrophy is the result of optic neuritis, 
with symptoms like those described under Papillitis. 
After the swelling of the nerve head subsides the out- 
line becomes more distinct and smaller in size, and the 
large and tortuous vessels become contracted. The 
papilla has a white appearance, sharply defined. The 
prognosis is always unfavorable. 

The treatment should be aimed at the cause, together 
with tonics and alteratives for the nerve lesion. 



136 OPHTHALMOLOGY FOR VETERINARIANS 

It is of the utmost importance, in passing one's judg- 
ment upon the soundness of an animal, that the optic 
nerves be examined — in fact, the whole fundus of the 
eye; for, however sound an animal may be otherwise, 
if the fundus is or has been diseased, it materially 
lessens the animal's value. In order to determine a 
pathologic condition one must become familiar with the 
normal fundus, and advantage should be taken of every 
opportunity to learn its details. 



CHAPTER XII 

DISEASES OF THE LENS 

Cataract.— A cataract is an opacity of the crystalline 
lens, its capsule, or both. Animals are as subject to 
cataract as man. The horse, dog, and cat are frequently 
seen with cataractous lenses. 

Normally, the lens is transparent, but as one advances 
in life it becomes less transparent and assumes a hazy 
appearance when viewed obliquely. This is due to an 
increase in its density. Under this condition the vision is 
probably as good as in early life, when the lens is much 
softer, though often in man the density becomes so great 
that near-sightedness is developed by virtue of changes 
in its refraction. In such instances elderly people read 
print without the aid of glasses, and they think, as is 
often remarked, they have their "second sight." Such 
cases, however, are apt to be followed by cataractous 
changes. 

Classification. — Cataracts are classified, according to 
age, density, course, etc., as congenital, senile, soft, 
hard, incipient, mature, primary, secondary, capsular, 
lenticular, stationary, progressive, traumatic, etc. 

When an animal is born with cataractous lenses it is 

137 



138 OPHTHALMOLOGY FOR VETERINARIANS 

the congenital type, and is due to faulty nutrition. A 
senile cataract occurs late in life when the lens becomes 
sclerosed, and is due also to faulty nutrition or to the 
absorption of toxins from the circulation; and here a 
toxic type might be mentioned, produced either by auto- 
intoxication or the ingestion of toxic agents, such as the 
ergot of rye, for example. Soft cataracts occur in the 
young and hard cataracts in aged subjects. An incipient 
cataract is one in its initial stage, before the vision has 
become impaired, while a mature cataract is a lens which 
has undergone complete change. This is also known as 
a "ripe" cataract, and is ready for extraction. A 
primary cataract is one that appears without apparent 
cause, while a secondary cataract follows disease of 
other structures of the eye, such as glaucoma, etc. 
Lenticular cataract is confined to the lens; it is also 
known as cortical or nuclear, according to the location 
of the opacity. When a cataract remains in the same 
condition for a long period of time it is said to' be sta- 
tionary. The posterior polar cataract is classified 
under this head, and also as congenital and capsular, 
and its cause differs from that of other cataracts. A 
progressive cataract is one that steadily advances to 
maturity. Traumatic cataracts are the result of either 
direct violence or accident during operations. 

As a rule, a cataract does not lessen the vision unless 
it is centrally located. There is no inflammation present 
that is dependent upon a cataract unless it is com- 



DISEASES OF THE LENS 139 

plicated with diseases of other structures. The size of 
the pupil is not affected unless iritis or glaucoma exist. 

When a cataract occupies the pupillary area the color 
of the pupil changes from its dense black to a bluish- 
white or gray appearance. 

In examining the lens for incipient cataract the pupil 
should be dilated by the use of atropin and illuminated 
by oblique light or the transilluminator, when spokes in 
the extreme border of the lens can be seen radiating 
toward the center. They can easily be seen through a 
strong lens by the aid of the ophthalmoscope. 

A senile cataract usually begins in this way, by 
branching or spoke-like opacities radiating from the 
periphery. 

As before mentioned, auto-intoxication has been 
hinted at as a cause of this type of cataract. The lens 
is a non-vascular body, and receives its nourishment 
from the ciliary processes through the circumlental 
space. It is suspended by Zinn's ligament, which not 
only fuses with the lens capsule, but apparently dips into 
the lens substance somewhat, producing a sort of 
serrated condition of the peripheral portion. It is at 
this particular point that the cataractous spokes appear 
to arise. 

A cataract of the senile type is divided into four 
stages — viz., incipiency, intumescence, maturity, and 
hypermaturity or degeneration. Nothing of importance 
is noticeable during the first stage, unless it be com- 



140 OPHTHALMOLOGY FOR VETERINARIANS 

plicated with pathologic changes in the chorioid and 
retina. The lens during the second stage becomes 
swollen because it has absorbed fluid, and the iris is 
pushed forward in consequence, but not until the 
striae reach the pupillary or, rather, central area, and the 
lens assumes a bluish-white color and becomes partially 
opaque, is vision disturbed to any great degree. 

A gradual mersion from the second to the third stage 
takes place when the lens becomes totally opaque; the 
excess of fluid is lost and it resumes its normal size. 
During this stage there is no fundus reflex, the pupillary 
area appears white and the vision is nil, though, if there 
is no fundus disease, light may be perceived and also the 
direction from which it comes. This is known as light 
perception and projection, which might be difficult to 
obtain in the animal. The operation for cataract (ex- 
traction) should be done during this stage. 

The fourth stage is indicated by a liquefaction of the 
cortical portion of the cataract by reason of fatty de- 
generation. 

The nucleus, however, retains its hardness, and 
remains so for years, floating in the milky-like liquid of 
the remaining portion of the lens within its capsule. 
In many cases the capsule itself sooner or later becomes 
cataractous, and when this occurs an operation of ex- 
traction is liable to be attended with complications. 

A secondary or capsular cataract often occurs after 
the extraction of the lens if an extraction is done 



DISEASES OF THE LENS 141 

without removing the entire capsule at the time. Ex- 
traction of the lens in and with the capsule is practised 
by many operators, but with animals it would be a 
hazardous undertaking, as it requires much time, care, 
and special skill, besides there is greater danger of losing 
much vitreous and possibly the eye itself. 

A capsular cataract is due to a proliferation of cells 
upon its surface and a thickening of the capsule, which 
does not occur until some time after extraction. It 
eventually diminishes the effect of the operation. In 
hypermature cataracts this change takes place in com- 
mon with the degeneration of the lens substance. 

In some instances a cataract will clear up spon- 
taneously, though when it becomes complete there is 
less probability of it doing so. In traumatic cataract, 
when the lens is soft and the capsule is completely 
ruptured, so that the lens substance escapes, it is usually 
absorbed. This process of absorption sometimes takes 
place very rapidly, even within forty-eight hours after 
the injury. In traumatic cataract of old and hard lenses 
this ready absorption does not take place; on the con- 
trary, the lens remains cataractous, and often swells to 
such a degree as to produce much increase of tension 
and severe pain, when immediate extraction is often 
necessary. 

In the early stages of cataract massage over the 
closed lids has apparently benefited some cases, while 
in others it has seemed to create an increase in the 



142 OPHTHALMOLOGY FOR VETERINARIANS 

rapidity of the cataractous formation. Drops of various 
kinds have been placed upon the market which are 
claimed to promote absorption, but, having been tried 
by eminent men in the profession, they have been found 
to have no value in this respect. After a cataract has 
been formed there is no treatment except relief by opera- 
tion. 

Luxation of the Lens. — The lens becomes dislocated 
by reason of traumatism, extreme muscular exertion, 



Cornea 
Dislocated lens 



Cilia 




Fig. 31. — Vertical section of eyeball of horse, showing dislocated lens 
in anterior chamber. Dotted line indicates normal position. 

sudden reduction of tension, extreme increase of ten- 
sion, atrophy of the fibers of the zonule of Zinn, particu- 
larly in hypermature cataract. In short, by stretching 
or rupture of the suspensory ligament. 

In cases of partial luxation the border of the lens may 
be tilted backward or forward. In complete luxation 
the lens may be forced backward into the vitreous, and 
in rare instances it is forced forward beneath the con- 



DISEASES OF THE LENS 143 

junctiva. In man it has been driven through the coats 
of the globe into Tenon's capsule. 

Luxation backward into the vitreous is the most 
common. It may remain there without causing any 
special reaction, though it frequently causes, in trau- 
matic cases, hemorrhage and inflammation of the inner 
coats of the eye, eventually resulting in shrinking of the 
globe. 

In a dislocated cataractous lens the treatment, in 
man, would be to allow the lens to gravitate into the 
anterior chamber, fix it with a needle, and extract it 
by the usual method, by passing a loop or wire spoon 
beneath it. This method would be impracticable in 
animals. One might attempt to fix the lens if it can be 
favorably placed and scoop it out carefully. An outer 
or inferior section should be made, as one has a greater 
field in which to work, and the wound can be more 
readily inspected and cleansed. 

Lenticonus. — This is an anomalous condition, and 
has been found in the pig and rabbit by Hess, as de- 
scribed by Norris and Oliver. In each case the lens 
was without a nucleus and cone shaped, with the apex 
pointing backward. Although the anterior portion was 
clear with normal capsule, the lens substance had under- 
gone granular degeneration. Several investigators have 
found this condition in the eyes of rabbits. 



CHAPTER XIII 

OPERATIONS FOR CATARACT 

There are two principal operations for cataract — 
discission and extraction. The former is employed only 
in cases of congenital cataract, or when it is acquired 
in early life, when the cataract is soft and undergoes ab- 
sorption readily. 

Discission of Cataract. — The ultimate object of this 
operation is to produce absorption of the lens by break- 
ing up its substance by the use of a small knife-needle. 
The eye should be washed with an antiseptic solution of 
bichlorid of mercury, i : 5000, and the pupil dilated with 
atropin solution of 1 per cent. It should then be anes- 
thetized with cocain of 5 to 10 per cent, solution. The 
speculum may be used, or an assistant may hold the 
lids apart. The knife-needle is then passed through the 
cornea near its margin — never through the center — 
and pushed diagonally through the lens capsule and into 
the lens substance. An upward and downward move- 
ment of the handle causes the lens to be cut and broken. 
The knife-needle must be withdrawn in the direct line 
of its entrance. 

If absorption of the lens substance does not readily 

144 



OPERATIONS FOR CATARACT 145 

occur, this operation may be repeated; in fact, several 
operations may be necessary to produce complete ab- 
sorption. 

In some cases following discission swelling of the 
lens takes place, which causes pressure upon the anterior 
drainage canal (canal of Schlemm), producing an in- 
creased tension, often accompanied with much pain. 
If this persists after the use of ice-cold applications and 
rest, it may be necessary to make an incision of the 
cornea at its margin and allow the lens substance to 
escape. In severe cases of increased tension an iridec- 
tomy may be performed. Iritis of a severe type may be 
produced by irritation from floating particles of the 
lens. This must be met by the use of atropin and hot 
applications locally, purgatives, rest, and a dark stall. 

Extraction of Cataract. — This operation is adapted 
for all hard cataracts, and for such as a discission would 
be deemed inadvisable. 

Before attempting this operation, however, there are 
many things to consider. Should the fundus be dis- 
eased or the optic nerve atrophied, the operation would 
be of no practical value. To determine whether the 
fundus is normal the animal should be placed in a dark- 
ened room, the better eye covered, and light from a 
small mirror reflected on the eye being tested. Note the 
action of the pupil, and whether the animal notices the 
light as it is placed at various points of the fields — above, 

below, outward, and inward. If the pupil reacts, and 
10 



146 OPHTHALMOLOGY FOR VETERINARIANS 

notice is taken of the movements of light by motion of 
the ej^eball, it is fairly conclusive that the fundus is 
normal. 

The conjunctiva must be free from secretion and the 
nictitans membrane and lacrimal apparatus free from 
hypertrophy and inflammation. In man the urine is 
always examined to determine the absence of albumin 
and sugar. The animal should be free from cough and 
any disease which may cause sudden exertion. The 
bowels should be freely opened the day before the 
operation. 

Preceding the operation the conjunctival sac should 
be examined, and washed with a saturated solution of 
boric acid or a 1 : 5000 solution of corrosive sublimate. 
The long hair about the eye may be trimmed with 
scissors, and the parts washed with soap and water, 
followed with one of the above solutions. 

In man we use cocain of about 5 per cent, solution, 
but in animals it is better to use complete general 
anesthesia, as any sudden movement during the opera- 
tion may cause a serious accident. 

The various steps of the operation are: Applying the 
speculum, corneal section, iridectomy, cutting the 
capsule, extracting the lens, cleansing the wound 
(toilet), applying the dressing. 

Some operators prefer to use atropin previous to 
the operation to dilate the pupil. Some also prefer 
not to use the speculum, but rather to have a com- 



OPERATIONS FOR CATARACT 147 

petent assistant hold the lids open -with the fingers or 
retractors. There are objections to this latter method, 
however, as the hands of an extra person are always 
in the way, and pressure upon the eyeball may be 
made, which must, in all cases, be avoided. The 
conjunctiva of the globe must be grasped with the 
fixation forceps at a point opposite to the corneal 
section. The Graefe cataract knife may then be passed 
in at the corneal margin, sliding it along through the 
anterior chamber, being careful not to wound the 
iris, and the counterpuncture made at a point directly 
opposite, at the margin; carry the blade forward, and 
with one sweep, if possible, complete the section, fol- 
lowing the margin all the way as closely as possible. 
The success of this step depends upon two principal 
points — the skill of the operator and an exceedingly 
sharp knife. Each knife should be tested before the 
operation, and the point should pass through the test- 
drum head by virtue of its own weight. 

In man the corneal section is usually made upward, 
passing the knife through the cornea from the external 
portion in each eye, making the counterpuncture toward 
the nose. A section of a little more than one-third of 
the cornea is usually made. It is better to make a large 
rather than a too small section, so that the lens can be 
readily extracted without undue pressure and wound- 
ing of iris and adjacent structures, when there is less 
danger of inflammation of these structures following, 



148 OPHTHALMOLOGY FOR VETERINARIANS 

also less danger of complications attending the opera- 
tion. The section should be made by a pushing or pull- 
ing movement, with as little sawing motion as possible, 
as there is less danger of serration of the edges of the 
wound, and healing takes place more readily. When one 
considers the anatomic relations, it will be seen that 
the margin of the cornea must be closely followed. 

Iridectomy is the next step, though this is omitted 
in simple extraction. With an iridectomy there is less 
danger of prolapse of the iris through the wound, and 
the lens is delivered more readily. On the other hand, 
the pupil is less regular and the vision may not be as 
perfect, though just as good visual results have been 
attained following an iridectomy as by the simple ex- 
traction. 

Iridectomy is performed by passing a special iris for- 
ceps through the wound, grasping the pupillary border 
of the iris, withdrawing it through the corneal wound, 
and snipping off a small portion with a special iris 
scissors. 

The next step is the cutting of the capsule. Some 
operators prefer to rupture the capsule by tearing out 
a portion with a special capsule forceps. A much better 
method is cutting out a square window by the use of 
the capsulatome. This instrument is passed in, pushed 
downward, then horizontally, then upward, then again 
horizontally to the starting-point. This square section 
often comes away with the lens, leaving a clear pupil. 



OPERATIONS FOR CATARACT 149 

The next step is the extraction of the lens. With a 
special spoon-shaped instrument make pressure over 
the cornea at a point about three-fourths of the corneal 
width, in the opposite direction from the incision. 
This causes that portion of the lens to tilt backward 
and the opposite portion to tilt forward and present it- 
self in the wound. Counterpressure. may be made with 
a small spoon-shaped instrument on the sclera, near 
the corneal section, allowing the lens to slide over this 
instrument, with which its delivery may be greatly 
facilitated by gently lifting it outward and upward, at 
the same time keeping up the pressure with the other 
instrument, gradually following the lens upward until 
its extraction is completed. Any remaining portions 
of the lens substance or capsule fragments may be 
teased out by the same method. 

Protruding portions of the iris must be replaced 
with a small spatula with rounded edges, or a small 
shell-spoon, and all blood-clots and shreds must be 
cleared away from the wound, so that the edges will 
readily unite. The speculum may then be removed 
and the eyelids closed. A sterile dressing and bandage 
must then be applied. 

Accidents Attending the Operation. — Numerous ac- 
cidents may occur during the course of the operation. 
In making the corneal section the knife may be caught 
in the iris, in which case it may be gently withdrawn 
until disengaged and then pushed forward. If it 



150 OPHTHALMOLOGY FOR VETERINARIANS 

cannot be disengaged readily, it may be pushed along, 
slightly tilting the point of the knife forward, until it 
again emerges into the anterior chamber, to the op- 
posite corneal margin at the point of counterpuncture. 
This accident is usually due to a shallow anterior cham- 
ber and lack of skill. Always keep the knife-blade in 
view, in the anterior chamber, between the cornea and 
the iris. When the iris is punctured or cut, hemorrhage 
in the chamber is likely to follow. This occludes one's 
vision, but, as a rule, does no harm, as it is stroked out 
with the lens or is absorbed soon after the operation is 
completed. When the iris is cut, an iridectomy will 
have to be done to get the best visual results. 

Prolapse of the iris sometimes occurs when a large 
portion of this body passes through the corneal wound. 
In the majority of cases this can easily be replaced 
by the shell-spoon or replacer. If it cannot be so replaced, 
it must be grasped with the iris forceps and cut off near 
the wound. 

The lens capsule may also be cut in the passage of the 
knife through the anterior chamber. This weakens the 
resistance, and pressure of the lids or too much pres- 
sure upon the eyeball with the fixation forceps may 
cause the lens to be delivered spontaneously as soon as 
the corneal section is completed. If no vitreous follows 
this accident, the operation may be completed in the 
usual way. If vitreous escapes when the lens is ex- 
tracted, the speculum should be immediately removed 



OPERATIONS FOR CATARACT 15 1 

and the eye closed. After a minute's rest the lid may be 
raised with the finger, and the escaping portion of 
vitreous cut away with a pair of small sharp curved 
scissors. The lid should be immediately closed and 
the dressing applied, but too much pressure over the 
closed lid must be avoided. The escape of a little 
vitreous does no special harm, but the loss of a large 
quantity lessens the support of the retina, and it may be- 
come detached from its normal position. 

Iritis and cyclitis follow extraction in a small per- 
centage of cases. It is often due to irritation by re- 
tained portions of the lens substance, also to constitu- 
tional diseases, and severe traumatism during or fol- 
lowing the operation. The condition must be met by 
the use of atropin and the usual treatment for iritis. 

Delayed healing of the wound sometimes occurs, 
even when the wound is free from capsule, lens, or 
vitreous substance. Spasmodic contraction of the lids, 
too great pressure of the bandage, and supervening 
glaucoma must be looked for. If, after these conditions 
have been corrected, the wound still gaps, the edges 
may be touched with the silver nitrate stick. 

Dressing. — A light pad of absorbent gauze should be 
placed over the eye and retained with strips of adhesive 
plaster. It is well to place a layer of absorbent cotton 
between the layers of gauze. Over this a suitable 
metallic mask may be placed to prevent the eye from 
injury in the act of rubbing. The mask should be 



152 



OPHTHALMOLOGY FOR VETERINARIANS 



large enough to rest on the bony structures about the 
eye and not on the eye itself. It may be sewed into a 
canvas or leather support, and this fastened over the 
ears and under the jaw by means of buckled straps. 

In the human subject some surgeons let the dressing 
remain five days before removing it, when the wound 
will be healed. Others prefer to dress the eye and ex- 




Fig. 32. — Simple eye-protector for horse. Buckles on the ends of the 
straps are not shown. 

amine it every day. There are some objections to 
both these methods. If, after twenty-four to forty-eight 
hours, the animal has done itself no injury, and there is 
no evidence of secretion on the dressing next the eye, 
it should be disturbed as little as possible. If there be 
secretion present, a clean dressing should be replaced, 
after gently washing the closed lids with a warm boric 
acid solution. 



OPERATIONS FOR CATARACT 



153 



One will have to use much judgment in each case as 
to his after-treatment, which will depend greatly upon 
his knowledge of existing conditions, and the result of 




Fig- 33- — Brusasco's eye-protector for the dog. 

an operation will depend very largely upon such knowl- 
edge and skill. 

If the pupil is clear, and there is no evidence of cap- 
sular and iritic adhesions in the pupillary area, the vision 




Fig- 34- — Brusasco's eye-protector applied. 

will be fair. Of course, we must always take into ac- 
count the refraction of the lens which has been re- 



154 OPHTHALMOLOGY FOR VETERINARIANS 

moved. In man, this can be replaced by a glass lens in 
front of the eye, but in animals this is altogether out of 
the question at the present time. However, where the 
animal was once blind, it can now see enough to travel 
about, though, if of a highly nervous temperament, it 
may shy until it becomes accustomed to its changed 
condition. 



CHAPTER XIV 

RECURRENT OPHTHALMIA 

Recurrent ophthalmia is commonly known as 
"moon blindness" and periodic ophthalmia. It has no 
relation to the moon's changes, but, being subject to 
periodic attacks, it has been known by the latter name. 

It seems to be particularly confined to the horse, and 
the favorite site of inflammation is the uveal tract, 
though the whole structure of the eye may be involved. 
An initial attack may apparently get well, but in the 
course of thirty to ninety days it may recur, and if 
these recurrences continue the eye may be eventually 
lost. 

The true cause of the disease is not known, though 
it is supposed to be of bacterial origin. Koch found 
cocci in the aqueous, which when injected into the 
normal eye of a horse produced a typic ophthalmia 
with the loss of the eye. Other investigators have 
found various organisms, but none has been definitely 
determined to be the specific cause. The principal 
predisposing cause is heredity. Law says, "This heredi- 
tary susceptibility is so strong and pernicious that in- 
telligent horsemen everywhere refuse to breed from a 

155 



156 OPHTHALMOLOGY FOR VETERINARIANS 

mare that has once suffered from recurrent ophthalmia, 
and at the government studs in France not only is every 
unsound stallion rejected, but the service of a healthy 
stallion is refused to any mare which has suffered from 
disease of the eyes. A consideration for the future of 
our horses would demand that no stallion shall stand 
for the public service of mares unless he has been ex- 
amined and licensed as a sound animal." The months 
of spring have some influence in producing an attack, 
as well as pasturing on swampy lands, damp stabling, 
improper and overfeeding, intestinal irritation, local 
irritants, and debilitating diseases. These may all be 
exciting causes, yet there must be some specific bac- 
terium which is the primary factor. 

Symptoms. — The disease first shows itself by local 
irritation due to a low grade of uveitis, with a faint 
whitish flocculent deposit in the anterior chamber. 
There are later manifestations of iritis and cyclitis with 
photophobia. The pupil is sluggish in its action, even 
when mydriatics are employed. Exudates are thrown 
off from the iris and adjacent body, and are deposited 
in the dependent portion of the anterior chamber. 
In many cases a lymph deposit is diffused through the 
aqueous, imparting to it a milky appearance and en- 
tirely closing from view the pupillary area. The cornea 
becomes hazy from the presence of this material on its 
posterior surface and from cellular infiltration. If the 
inflammation is not too severe, it ceases in from twelve 



RECURRENT OPHTHALMIA 157 

to fifteen days, and the eye resumes its normal ap- 
pearance. During this period of quiescence the lesions 
due to the initial attack may be noticeable. In from 
one to three months a recurrence will take place, with 
much greater severity than the former attack. All the 
symptoms of a severe iridocyclitis prevail, together with 
an increase of the intra-ocular tension (glaucoma) and 
the formation of an opaque lens (cataract). The sclera 
about the ciliary border takes on a different aspect, 
being dark or bluish-black in color. The vitreous be- 
comes opaque, and after two or more attacks symptoms 
of degeneration appear, and the globe becomes shrunken 
and is apparently retracted. 

The disease seems to be most formidable, in that it is 
not satisfied with one eye, but in time attacks the fellow 
eye and destroys that also in like manner. Whether this 
is due to sympathetic involvement, as is often seen in 
man, which is reasonable to assume, or whether it is due 
to the original cause, is a question. The fellow eye is 
sometimes attacked and destroyed, even while vision 
remains in the eye which was first affected. 

Treatment seems to be of little value in most cases. 
Local conditions should be met by proper therapeutic 
measures, together with the observance of hygienic 
conditions and proper feeding. The animal should 
be isolated from other animals, and should not be used 
for breeding purposes. 



CHAPTER XV 

GLAUCOMA 

Glaucoma is characterized by an increase of the 
intra-ocular tension — that is, the eyeball is harder than 
normal, and its hardness may continue to increase until 
there is absolute resistance to pressure by the finger- 
tips. Make a practice of taking the tension in all dis- 
eases of the eye as a part of the routine examination, 
and acquaint yourselves with the normal tension of the 
eyes of different animals. This is done by pressing the 
eyeballs, above the cornea, over the closed lids, with 
the tips of the index-fingers; first gently pressing with 
one finger, and then with the other, as in testing for' 
fluctuation. There is an instrument devised for this 
purpose, called a tenometer, but with practice and ex- 
perience the finger-tips are reliable. 

The cause of increased tension is due to a damming 
up or failure of the lymphatics to perform their func- 
tion, the principal one being Schlemm's canal, located 
in the sclera, just anterior and external to the spaces 
of Fontana or the filtration angle of the anterior cham- 
ber. This angle is adjacent to the anterior portion of the 
ciliary body and the root of the iris. For this reason 

158 



GLAUCOMA 1 59 

atropin, or any other agent which causes a thickening of 
the iris at this point, should not be used in cases of 
glaucoma or in a subject predisposed to an attack, as in 
the first instance it will only increase the trouble and 
probably ruin the eye, and in the second instance it will 
induce an attack. 

The simple type of glaucoma comes on very gradually, 
is not accompanied with inflammation, and there is 
little or no pain. It occurs in both eyes. The tension 
may vary at different times, and often during the first 
stage it is not recognized. As the condition advances 
the pupils become somewhat dilated and sluggish, the 
cornea is clear or slightly hazy. The visual field is much 
contracted, and the acuity of vision is greatly reduced. 
The intra-ocular pressure is continuous and increases, 
and, because of this, the weaker portions of the head 
of the optic nerve give way and are pushed backward, 
and by an ophthalmoscopic examination a deep cup- 
ping of this portion of the nerve can be seen. The 
retinal blood-vessels seem to be lost at the margin of 
the disk, caused by the cupping and dipping down of 
the vessels at this point. This cupping of the disk 
varies in degree, according to the duration of the ten- 
sion. If the condition is not checked, vision will ulti- 
mately be destroyed. This simple type of glaucoma 
often becomes inflammatory in character. 

The inflammatory type of glaucoma is usually ac- 
companied with a great deal of pain, which may be 



160 OPHTHALMOLOGY FOR VETERINARIANS 

confined to the eyeball or the region about the eye. 
The globe is reddened and the large episcleral vessels 
are engorged. The cornea is hazy in appearance, and 
the pupil is enlarged and sluggish. The anterior cham- 
ber is shallow and the iris is pushed forward. The prog- 
nosis is extremely bad. 

This type is often secondary to diseases of the eye, 
such as iritis with adhesions, hemorrhages in the retina 
and chorioid, and to traumatism. It is also one of the 
conditions which accompanies recurrent ophthalmia in 
the horse. 

Treatment. — The object in the treatment of glaucoma 
is to relieve the pressure from Schlemm's canal and 
re-establish its function. In order to do this with a 
drug we must use a myotic, or one which causes a 
contraction of the pupil. Eserin in solution of \ to \ 
per cent., or pilocarpin in solution of i per cent., may be 
dropped into the eyes three times daily. In simple 
glaucoma this treatment is about all that is necessary, 
though it will have to be continued for months or 
perhaps years. 

In inflammatory glaucoma the same drugs are used, 
but if pain exists, as it most always does, it will be 
necessary to do an iridectomy. To get the best results 
a broad excision of the iris should be made near its base 
or root. The tension is often immediately reduced 
following this operation. A too sudden reduction of 
the tension may do harm, as the sudden inrush of blood 



GLAUCOMA l6l 

into the retinal vessels may cause them to give way, 
and an intra-ocular hemorrhage will be the result. For 
this reason, before doing an iridectomy, it is better to 
do a paracentesis, and allow the gradual escape of the 
aqueous and a gradual lessening of the tension. 
11 



CHAPTER XVI 

INJURIES OF THE GLOBE 

Injuries of the eyeball in general are simple con- 
tusions, with rupture, incisions, punctures, and lacera- 
tions. 

Contusions are produced by a blow with some blunt 
object. Simple contusions without rupture may be ap- 
parently trivial or much damage may be done. The 
results of simple contusions are paralysis of the sphincter 
pupillas, causing dilatation, rupture of the suspensory 
ligament, dislocation of the lens, rupture of the border 
of the iris, causing a separation and an opening (irido- 
dialysis), hemorrhage in the anterior chamber, sub- 
conjunctival hemorrhage, rupture of the chorioid, and 
hemorrhage in the chorioid and retina. Contusions with 
rupture of the globe is a frequent occurrence. Usually 
the rupture takes place about the sclerocorneal margin 
anteriorly. It may occur at any point, according to the 
direction of the blow. The posterior portion of the 
globe may also be ruptured in an irregular manner, and 
a general rupture and displacement of the internal struc- 
tures may occur. The following case, in a colored man, 
is a good illustration: The man was struck with con- 

162 



INJURIES OF THE GLOBE 163 

siderable force by a billiard ball in the left eye. He 
was seen twelve hours after the accident. The lids were 
badly swollen, the eye closed. Inspection revealed a 
rupture of one-third of the cornea near the inner margin. 
The anterior chamber was tilled with blood; the cornea 
was clear. The case was nursed along with cold anti- 
septic applications until the swelling subsided. The cor- 
neal rupture failed to heal readily, still there was no 
prolapse of the internal structures. After two weeks' 
treatment, when efforts seemed to be of no avail in 
saving vision, the eye was enucleated. The globe was 
found to have been ruptured posteriorly at a point op- 
posite to the anterior rupture, but much more extensive 
and in a crescentic shape, nearly three-fourths around the 
globe. This posterior rupture had readily healed; the 
sclera was firmly united. This goes to show that the 
remote rupture is often more extensive than that where 
the blow was received. In this case the lens was dislo- 
cated and the iris torn. About the anterior rupture the 
cornea was partly opaque or white in appearance. Had 
the globe been allowed to remain in the orbit it would 
have been of no value, as its function was destroyed. 
The globe would have shriveled (phthisis bulbi), and 
there would probably have been subsequent attacks of 
inflammation. 

Punctures of the globe are caused by pointed, sharp, 
or dull objects, and the result depends upon the location, 
depth, and the condition of the object — that is, whether 



1 64 OPHTHALMOLOGY FOR VETERINARIANS 

it is clean or dirty. Even if an object is apparently clean, 
it may carry bacteria with it into the eye and produce 
terrific reaction. Punctures through the cornea produce 
a loss of the aqueous and often a prolapse of the iris into 
the wound, which may become adherent (anterior syne- 
chiae) and interfere with the normal pupillary reaction, 
or the iris is drawn to one side, producing an irregular 
pupil. Punctures still deeper cause hemorrhage in the 
anterior chamber by ruptures of the iris vessels. Be- 
sides these, the lens becomes cataractous through 
rupture of its capsule. The lens often swells, and all 
the symptoms of glaucoma accompany the accident. 

A puncture of the ciliary body by a septic object 
should always be regarded with apprehension. Pro- 
lapse of the internal structures of the globe will depend 
upon the size of the puncture and the resistance of the 
external coats. Small punctures of the sclera posterior 
to the ciliary region are usually unimportant from a 
surgical point of view, though they often produce hem- 
orrhage within the eyeball and a localized scotoma. 

The results of an incision are very much the same as 
those of a puncture, though there is more probability 
of a better and more rapid union of the wound by sutur- 
ing the same. 

Lacerations are probably the most severe type of 
injuries to the globe. The result of a laceration depends 
upon the extent and the part injured. 

Injuries are nearly always confined to the anterior 



INJURIES OF THE GLOBE 165 

portion of the globe. A laceration heals much less 
readily than an incision, and is more liable to infection 
because of the ragged edges of the wound. Practically 
the same conditions of prolapse, dislocation of the 
internal structures, etc., take place in extensive lacera- 
tions as in punctures and incisions. 




Fig. 35. — Injury of the globe, two months' standing. The contents 
of the globe prolapsed. Enucleation was done and an artificial eye 
applied in due season. (Dr. Danner's case.) 

Complications. — In severe injuries of the globe the 
neighboring structures may be involved. The lids may 
be badly bruised, swollen, and ecchymosed; or they 
may be punctured, incised, or lacerated. The bones of 
the orbit may be fractured and displaced. The optic 
nerve may be ruptured, or atrophy follows because of 



1 66. OPHTHALMOLOGY FOR VETERINARIANS 

compression. Cellulitis of the orbital tissues may follow 
from infection. 

Treatment of Injuries of the Globe. — The main object 
in treatment is to save the function of the eye. If vision 
cannot be saved, our next object is to preserve the globe. 
In cases where much damage has been done, the vision 
destroyed, and the eye is unsightly, the most philosophic 
method would be to enucleate the globe and replace it 
with an artificial eye; but, for reasons unknown to the 
profession, an eyeball is often preserved when it is of 
no earthly use, and often when its ugliness is most con- 
spicuous to friends and passers by. 

Always remember the general principles of cleanliness 
and asepsis in the treatment of all these cases. Wounds 
should be cleansed of all foreign substances, for the 
danger of infection is often greater than that of the 
injury itself. 

Simple abrasions of the cornea, from blows of twigs 
or other objects, should be treated with applications of 
mild antiseptic washes, and an aseptic pad and bandage 
applied for protection. These superficial abrasions heal 
rapidly, and the epithelium is soon re-established if the 
wound is not infected. If the wound becomes infected, 
infiltration and ulceration of the cornea may follow, 
when the treatment would be the same as given under 
Ulceration of the Cornea. 

Perforating wounds of the cornea, in which the 
aqueous escapes and the iris is caught in the wound, 



INJURIES OF THE GLOBE 167 

require special treatment. After thoroughly cleansing 
the wound, the iris, if not wounded itself, may be re- 
placed, and, if it is centrally located, a mydriatic should 
be employed to draw it away from the opening and 
prevent adhesions. If the wound is near the corneal 
margin a myotic may be used for the same purpose. 
If the wound is extensive, and involves the iris with a 
protrusion of this tissue through the wound, the pro- 
truding portion may be excised and a mydriatic or myotic 
employed, according to the location of the injury. By 
watching the condition of the iris, and keeping the 
wound absolutely clean and protected with an anti- 
septic dressing, nature will produce wonderful results 
oftentimes in these cases. It is not advisable to stitch 
a corneal wound. 

If inflammation arises by reason of infection, more 
rigid antiseptic measures must be employed. After 
thoroughly cleansing the eye of all secretion the insuffla- 
tion of finely powdered iodoform, boric acid, or equal 
parts of these may be used, or an ointment of iodoform, 
with lanolin as a base, is of great value. Should inflam- 
matory reaction of the iris take place the general treat- 
ment of iritis must be employed. 

Wounds of the conjunctiva and sclera may be brought 
together with fine sutures. It is preferable to use a 
silk suture with a needle on both ends, and these passed 
through the tissue from within outward, the sclera and 
conjunctiva stitched separately. The ruptured parts 



1 68 OPHTHALMOLOGY FOR VETERINARIANS 

should be brought together evenly, and strict caution 
should be observed that none of the internal structures 
be caught in the inclosed wound. In all hopeless cases, 
more particularly when there is danger of sympathetic 
inflammation of the other eye arising, the globe should 
be enucleated. 

Injuries of the Globe, with Foreign Bodies Remaining 
in the Eye. — These are always to be looked upon with 
considerable apprehension. Such bodies may be small 
or large, sharp or blunt. A small sharp-pointed body 
may enter the eye and its place of entrance be hardly 
noticeable. Again, the body may be large enough to 
lacerate the globe. If the smaller body carries bacteria 
with it, it may do as much or more damage eventually 
than the larger body. These foreign bodies are com- 
posed of various substances, such as stone, glass, wood, 
lead, copper, iron, and steel. The wound is much like 
that of a puncture plus the presence of the foreign body. 
There is great danger of infection and irritation of the 
tissues in contact with the foreign body. 

It is always advisable to remove a foreign body if it 
can be located and readily reached. If the body is in 
the anterior chamber, it may be withdrawn through its 
source of entrance with a small forceps. If it has passed 
into the vitreous, it maybe necessary to make an incision 
in the sclera and remove it through that opening. 

When the media are clear, the body may be seen with 
the ophthalmoscope. If it is a substance which will react 



INJURIES OF THE GLOBE 169 

to magnetic attraction, the electromagnet is the instru- 
ment to use. It is made in two forms — the large or 
giant magnet, which has a lifting power of 400 pounds 
or more, and the hand magnet, which is sufficient in 
most cases. 

In making the scleral incision the eye should be drawn 
in the opposite direction, by an assistant, with a strong 
fixation forceps. Plunge the Graefe knife into the eye 
with the edge of the blade backward, and enlarge the 
opening in the act of withdrawing the knife. The in- 
cision should be made far enough back to prevent 
wounding the lens or ciliary body, and in a position as 
near the foreign body as possible. The magnet point 
is now introduced into the wound and the current 
turned on. The body will usually come in contact with 
the point, when it can be withdrawn. Authors gener- 
ally recommend making the scleral incision at a point 
between the insertion of the muscles, but the writer has 
made the incision through the belly of the internal 
rectus muscle in one case, and was successful in remov- 
ing steel from the vitreous without the loss of a particle 
of vitreous or injury to the ciliary body or lens. Such 
an incision must be made parallel to the muscle-fibers, 
which close and protect the scleral wound. 

When the body is embedded in the chorioid it may 
become encysted, and, if sterile, may do no particular 
harm, though it may be dislodged, drop into the vitreous, 
and cause irritation and inflammation. If lodged in the 



170 OPHTHALMOLOGY FOR VETERINARIANS 

lens, it may also do no harm for a time, except to pro- 
duce a traumatic cataract, though the lens may swell 
and glaucomatous symptoms follow; or the lens, in young 
subjects, may become gradually absorbed, and the body 
will drop down, irritate the ciliary body, and produce 
cyclitis, iritis, chorioiditis, etc. 

Enucleation of the Globe. — As before stated, it is 
better, in all hopeless cases, to enucleate the globe. 
This is much more difficult to do in the quadruped than 
in man, because of the large retractor muscle. The 
steps of the operation are as follows : 

General anesthesia should be used in all cases, as we are 
not justified in causing the dumb beast to suffer more 
pain than is necessary. Wash the eye and the surround- 
ing parts with soap and water, followed by an antiseptic 
solution. Apply the speculum, or have an assistant 
hold the lids open with retractors. Make an incision 
through the conjunctiva, around the corneal margin, 
preserving as much of the tissue as possible. Under- 
mine the conjunctiva as far back as the insertion of the 
muscles, keeping as close to the sclera as possible. 
Pick up the muscles individually with the tenotomy 
hook, and cut them, with the small carved scissors, 
near their tendinous insertion. Cut away, gradually, 
the insertion of the retractor muscle, then pass in the 
strong curved scissors, grasp the optic nerve, and 
divide it with one snip if possible. In doing this the 
handle of the scissors must be raised, not lowered, as 



INJURIES OF THE GLOBE 



171 



there is danger of cutting the sclera itself. The globe 
can then be gradually pried out and any adhesions cut 
away. 

When the globe has been removed, the hemorrhage 
can easily be stopped by placing a dry aseptic gauze 




Fig. 36. — Enucleation of the eye. This is an old method and is used 
today by many operators. • It seems, however, that the use of ether, the 
relief of pain, and more careful dissection would be a more scientific and 
humane procedure. 



within the capsule. When hemorrhage has ceased, 
withdraw the gauze and close the eye, when the tis- 
sues will contract and come together naturally. Some 
surgeons close the wound with a puckering suture 
through the conjunctiva, but this is hardly necessary 



172 OPHTHALMOLOGY FOR VETERINARIANS 

in the animal. It is well to place some absorbent 
powder on the fissure and apply a compress bandage. 

Healing takes place readily, and a good stump is 
soon formed for an artificial eye. These, for the animal, 
are usually made of hard rubber, as they are less easily 
broken, and the coloring conforms more to animals' 
eyes than those made of glass. 

An artificial eye should not be placed until the wound 
is healed and there are no inflammatory symptoms 
present. 

Prolapse of the Eyeball. — It is understood by some 
of the laity that "the eyeball can be taken out, scraped, 
and put back again into the orbit." Any one with a 
knowledge of the eyeball and its muscular attachments 
can readily see the folly of this assumption. In the 
dog, however, the eyeball is not held very securely 
in the orbit, because the anterior bony arch is wanting, 
and the eyeball is supported only by the ligamentous 
attachments and the lids. For this reason, the eyeball 
of the dog is often prolapsed or dislocated forward by 
traumatism. It is said also to prolapse by reason of 
inflammatory processes within the globe, but this 
cause must be exceedingly rare. It is more probable that 
progressive tumors within the orbit might be the cause. 

Prolapse of the eyeball presents a very peculiar and 
ugly appearance. The writer once saw an English bull- 
dog whose eyeball was dislocated outward and down- 
ward by fighting with another dog. It was held in this 



INJURIES OF THE GLOBE 173 

condition by contraction of the orbicularis palpebrarum. 
This was a simple dislocation, without rupture of the 
conjunctiva or any of the muscles of the globe. 

Treatment. — If the eye cannot be readily put back 
into place, it will be necessary to produce general 
anesthesia in order to allay the sensitiveness of the 
cornea and relax the contracted muscles. Then, with 
gentle pressure with the thumbs and ringers over the 
outer and inner portions of the globe (avoiding pressure 
on the cornea), reduce it to its normal position. If 
you fail in doing this, make traction of the upper lid 
outward with an elevator. If you still fail to reduce it, 
the outer tendon of the orbicularis may be divided, 
when it can readily be reduced. This must be brought 
together again with sutures in order to support the 
globe, or it may be again dislocated spontaneously. 
If too long a time elapses before the reduction of the 
globe, the cornea becomes dry and hazy by reason of 
exposure. It soon resumes its normal transparency, 
but if it does not it must be treated as a superficial 
keratitis. 



CHAPTER XVII 

FRACTURE OF THE ORBIT 

Fracture of the orbit takes place usually near the 
orbital ridge of the frontal bone, though any bone of the 
orbit is subject to fracture by direct injury or concussion. 

Horned animals receive such injuries by fighting with 
other animals, or the injury may be self-inflicted while 
suffering with colic and other severe pain. 

When fracture of the orbital ridge takes place, crepita- 
tion may be felt while manipulating the parts, or the 
fractured part may be entirely displaced and deformity 
result. Fracture of the inner walls of the orbit may 
result in blindness (amaurosis) of the eye by pressure 
upon the optic nerve. Cellulitis and abscess of the 
orbital tissue may follow fractures caused by penetrat- 
ing wounds. 

Treatment. — Cold applications to prevent or reduce 
swelling and inflammation. Remove all dirt and foreign 
substances from the wound and apply antiseptic dress- 
ings. If an abscess forms, it must be drained externally 
by opening the wound with an aseptic probe. The wound 
must be kept open, and this can be done by placing in it 
a small wick of iodoform gauze, which may be held in 
place with aseptic absorbent gauze and bandage. 

174 



FRACTURE OF THE ORBIT 175 

When atrophy of the optic nerve takes place from 
pressure, very little can be done. If cellulitis and ab- 
scess are not controlled by the above measures, it will 
be necessary not only to enucleate the eyeball, but, 
in many cases, to cut away all the tissues in the orbit 
(exenteration), as the pus may burrow through the 
sclera, causing a panophthalmitis, or it may endanger 
life by extending to the meninges of the brain. 



CHAPTER XVIII 

PARASITES OF THE EYE 

Parasites of the Eyelids. — The eyelids are subject 
to the invasion of various parasites as follows: 

Pediculi {Lice). — These are often seen along the 
margin of the lids when present on other portions of 
the body. 

The eggs are found embedded or deposited near the 
lashes, and are often covered with crusts resulting from 
the secretion caused by their irritation. They produce 
a marginal blepharitis. The crusts should be softened 
with the yellow oxid of mercury ointment and removed. 
A piece of absorbent cotton, dipped in absolute alcohol 
and gently rubbed over the lids, will catch and remove 
the lice and their eggs. 

The Filaria palpebralis, discovered as early as 1429 
on the conjunctiva of the horse, is a cylindroid worm, 
8 to 15 mm. long, and thin at the extremities. 

The presence of this parasite causes an inflammation, 
varying from a slight to a severe conjunctivitis, with 
swollen and painful lids. 

Law mentions a case in which "the lids were firmly 
closed, the flow of tears abundant; the cornea was vas- 

176 



PARASITES OF THE EYE 177 

cular in its outer portion, with a surrounding area of 
opacity, which was followed with a bluish-white opacity 
of the whole cornea excepting the inner canthus. Under 
treatment there was a general improvement, but a month 
later there was a new attack, and five filaria were dis- 
covered under the eyelids. The cornea became opaque 
and permanent blindness ensued." 

In some cases there are no symptoms to indicate the 
presence of the parasites. The only way to diagnose 
the trouble is in finding the worms, and in many in- 
stances this is not an easy thing to do, as they may be 
concealed within the conjunctival folds, and are not 
sufficiently active unless the surfaces are quite moist. 

Filaria Lacrimalis Boms. — This resembles the worm 
last described. The female is from 20 to 24 mm. in 
length. It is usually found on the conjunctiva at the 
inner angle. 

The symptoms excited by the presence of this para- 
site resemble those last described — viz., a certain 
amount of swelling of the lids, partial ptosis and lacri- 
mation, together with inflammation of the conjunctiva 
and cornea. 

The worm can readily be seen in motion on a moist 
eye if carefully looked for. 

The Demodex folliculorum, commonly called the 
"pimple mite," is often found in the miebomian glands 
of the horse, dog, and sheep. As a rule it does not 

cause any marked disturbance. 
12 



178 OPHTHALMOLOGY FOR VETERINARIANS 

The Trombidium, an extremely small silky worm, 
invades the margin of the lids of the dog. Its more com- 
mon site is at the outer and inner canthi. The symptoms 
produced by this are not marked. 

The Trichina is said to have been found in the muscles 
of the eyelids, as well as in other muscles of the body. 
They cause swelling of the lids which is usually pain- 
ful, conjunctivitis, etc. The general symptoms of 
trichina are also present. 

The Hemopis sanguisuga, the horse leech, has been 
found clinging to the lids and conjunctiva of the horse 
under favorable conditions. 

Parasites Found Within the Eyeball. — The Filaria 
oculi equina, also known as the Filaria papulosa and the 
Filaria pellucida. This is not infrequently seen in the 
eye of the horse. It was known as early as the seven- 
teenth century, and has been discovered by various 
observers in this country and in Europe. 

It seems to be more prevalent among animals which 
are allowed to graze in wet pastures in moderate cli- 
mates. 

It is described as a thread-like worm, from 22 to 35 
mm. long, the male being the longer, with spiral tail, 
and reddish-white in color. 

Law describes the symptoms as follows: "Exception- 
ally the worm causes no inflammation, and it can be 
seen actively bending and unbending itself in the form 
of a loop, a figure-of-eight, or a spiral, in the anterior 



PARASITES OF THE EYE 1 79 

chamber. Usually there is considerable inflammation, 
closure of the lids and watering of the eyes, redness of 
the mucosa, clouding, and even vascularity of the 
cornea. Still, in a majority of the cases, a portion of the 
cornea remains sufficiently transparent to allow the 
movements of the worm to be seen. Sometimes it will 
temporarily retreat through the pupil and disappear 
behind the iris. Sometimes only one eye is involved, in 
other cases both eyes, and in some instances two or even 
three parasites are found in one eye." 

If the worm can readily be seen in the anterior cham- 
ber, an incision may be made in the margin with a 
cataract knife, when the worm may be grasped with a 
small pair of forceps and withdrawn. Cocain must 
be used to anesthetize the cornea and strict antisepsis 
observed. Much care must be observed not to wound 
the iris or the cornea in this operation. 

The Cysticercus Cellulosa. — This has been found in 
various portions of the eye — in the vitreous, the chorioid, 
retina, the anterior chamber, the muscles of the globe, 
and beneath the palpebral and bulbar conjunctiva. 

It has been found in the eye of man, the horse, the dog, 
and the pig. When it appears in the outer coats of the 
eye it is described as a white ovoid body. Within the 
vitreous "the cysticercus becomes visible as a bluish- 
white bladder" (Duane). When in the anterior chamber 
it has the appearance of a white cyst upon the iris. 



180 OPHTHALMOLOGY FOR VETERINARIANS 

Within the eyeball it is usually stationary, though it has 
been seen to make quick, active movements. 

Inflammation of the internal structures usually follow 
its entrance into the eye; detachment of the retina and 
cataract occur, vision is eventually lost, and the globe 
becomes atrophied. 

Attempts have been made to remove the organism by 
making an incision in the sclera and grasping it with a 
small pair of forceps; and, if it is in a position where it 
can readily be reached, this may be done; but, in the 
animal, one would assume a great risk in not being able 
to grasp it, and much damage would be done the globe 
in making the attempt. 



CHAPTER XIX 

THE PRINCIPLES OF VISION 

Vision is dependent upon light. Rays of light from 
a distance are parallel, while those from near objects are 
divergent. 

Refraction 1 means the turning or bending of rays of 
light as they pass through an object that is denser than 
the air. A good illustration of this is the apparent bend- 
ing of a spoon upward when placed in a glass of water, or 
the displacement of an object when seen through a 
prism. 

The index of refraction is the resistance of the object 
through which the light passes as compared with air, 
which is taken as i. 

When parallel rays of light pass through a plate-glass 
with both surfaces parallel they are not refracted, but 
emerge as they entered, but when they pass through a 
glass that is thicker at one edge than the other (a prism), 
they are deviated, or refracted from the apex toward the 
base, or the thicker portion of the prism. The angle of 
refraction— that formed by the incident ray with the 

1 Only a primary description of refraction will be considered. For 
a more complete study of refraction of light, the writer would refer the 
student to some good work on physics. 

181 



182 OPHTHALMOLOGY FOR VETERINARIANS 

refracted ray — depends upon the strength or degree of 
the prism. Prisms are numbered from § degree up. 

Spheric lenses — those cut from a sphere — are refrac- 
ting lenses. The convex or plus spheric lenses — of 
which the crystalline lens of the eye is a type — collect 
rays of light at a point on the opposite side; while 
concave or minus spheric lenses diverge rays of light 
on the opposite side. Rays passing through the optical 
center of a lens are not refracted. 




Fig. 37. — Principal focus of a convex lens. The parallel rays a, b, c, d 
are refracted by the lens so as to unite at the point F on the axis P; the 
ray P undergoes no refraction. F is the principal focus, (de Schweinitz, 
"Diseases of the Eye.") 

The point at which parallel rays are collected is the 
principal focus of the lens. The distance of this point 
from the optical center of the lens depends upon the radii 
of curvature and its index of refraction. Rays which 
diverge, back again through the lens, become again 
parallel. 

When rays come from an object nearer than "infinity" 
■ — supposed to be about 20 feet — they diverge, and are 



THE PRINCIPLES OF VISION 183 

collected at a point on the opposite side of the lens, at a 
greater distance from the optical center of the lens than 
the principal focus. The nearer the object is to the lens, 




Fig. 38. — Conjugate focus of a convex lens. The two dots in the axis 
represent the principal foci, one being marked F. Rays diverging from 
converge after refraction to the point F', farther than the principal 
focus. Rays from F' also converge after refraction to O. and F are 
conjugate foci, (de Schweinitz, "Diseases of the Eye.") 

the greater is the divergence, and the farther is the con- 
vergence on the opposite side. These two points — the 
point of divergence and the point of convergence — are 




Fig. 39. — Virtual focus of a convex lens. Rays from the point O, 
less than the principal focal distance, diverge after refraction as if they 
came from the point V. V is the virtual focus of O. (de Schweinitz, 
' Diseases of the Eye.") 

known as the conjugate foci. These points are at an 
equal distance when the point of divergence is at a dis- 
tance twice the focal distance of the lens. 



1 84 OPHTHALMOLOGY FOR VETERINARIANS 

The virtual focus of a convex lens is the point at which 
rays meet in a backward direction on the same side of 




Fig. 40. — Principal focus of a concave lens. Parallel rays a, b, d, e, 
after refraction by the concave lens L, are rendered divergent as if they 
came from the point F on the axis c. The ray c is not refracted. F, the 
principal focus of a concave lens, is virtual, (de Schweinitz, "Diseases 
of the Eye.") 




Fig. 41. — Virtual image of a convex lens: C, D is the object; C, D' is 
the virtual image, erect and magnified, (de Schweinitz, "Diseases of the 
Eye.") 

the lens to which they diverge, when the point of these 
divergent rays is nearer to the lens than its principal 



THE PRINCIPLES OF VISION 185 

focus. In this case the rays on the opposite side of the 
lens, instead of converging, continue in a divergent 
course. 




Fig. 42. — Virtual image of a concave lens: 0', B' is the virtual image 
of the candle; 0, B, erect and diminished in size, (de Schweinitz, "Dis- 
eases of the Eye.") 

The virtual image, seen through a convex lens, is 
magnified, while that seen through a concave lens is 
reduced. 




Fig. 43. — Image formed by a convex lens: 0, B is the object; 0', B' is the 
inverted image, (de Schweinitz, "Diseases of the Eye.") 

The image formed by a convex lens is inverted. This 
is so with the image formed upon the retina. (As an 
example, look at the image on the ground-glass of a 
camera.) Following the refraction of this image for- 



1 86 OPHTHALMOLOGY FOR VETERINARIANS 

ward, it again becomes upright. (As an example, place 
a lantern-slide, inverted, in a "magic lantern," and the 
picture is projected upright on the screen.) 

Lenses used for the correction of refractive errors — 
spectacle lenses — are the spheric, concave and convex, 
and cylindric lenses. The spheric lenses are cut from 
a sphere, that is, the surfaces have an equal radii of 
curvature. Such lenses are called biconvex or bicon- 
cave. Those with a plane surface on one side and a 
curved surface on the other are called planoconvex 
and planoconcave spherics. Cylindric lenses are cut 
from a cylinder, and refract at right angles to the axis 
of the cylinder. These are also convex and concave. 

Convex lenses are called plus ( + ) and concave lenses 
are called minus (— ). 

Lenses are now numbered according to their focal 
length in metric measurements. A lens whose focal 
length is i meter is called a i diopter lens. A lens of 
2 meters focal length, 0.50 diopter; one of \ meter focal 
length, 2 diopters. A meter equals in the English system 
39.37 inches. 

A plus one diopter spheric lens is designated thus, 
+ 1. 00 D. S. A minus one diopter spheric lens is written, 
— 1. 00 D. S. In writing for plus or minus cylinders, 
the same signs are used before the number, but in place 
of the S. a C. is used, and, following this, the axis of 
the cylinder is indicated, thus: +1.50 D. C. Ax. 90 ; 
-2.00 D. C. Ax. 180 . 



THE PRINCIPLES OF VISION 187 

A plus lens is neutralized by placing a minus lens of 
equal "strength" before it. For example, place a +1.00 
D. S. before a -1.00 D. S. and it has the effect of a glass 
whose sides are parallel. . ■ 

When the rays of light enter the eye from an object 
at infinity, that is, from a distance of 20 feet or more, 
the normal eye should be at rest, and the object will be 
"focused" or formed sharply upon the macula. The 
image on the retina is inverted. The rays cross at a 
point which is, approximately, in man 15 mm. anterior 
to the retina and 5 mm. posterior to the cornea. This 
is according to a schematic eye devised by Donders. 
(These distances would be relative in animals' eyes, 
according to the size of the eye.) An object 1 meter 
long vertically, placed at 15 meters distance from the 
eye, would produce a retinal image in vertical measure- 
ments, 1 mm. The size of the retinal image is influenced 
by the variations of the visual angle, and the latter varies 
according to the size and distance of the .object from the 
eye or the optical center of the lens. 

The acuity of vision is the ability to see objects of a 
certain size and at a certain distance distinctly. This 
depends upon a normal visual apparatus and proper 
light. Under normal conditions the visual acuity of 
animals of a kind should be the same. A bird, however, 
can see a grain or creeping thing at a much greater 
distance than can a cow or horse. They, therefore, 
have a greater visual acuity. Man can count the bricks 



1 88 OPHTHALMOLOGY FOR VETERINARIANS 

of a building when near to it, but at a distance he can 
only discern the outline of the structure. It is the nor- 
mal visual acuity that we seek to obtain in man when we 
correct the vision in cases of refractive errors. Fuchs 
says: "We select for the test not one, but two parallel 
lines, and then determine the greatest distance from the 
eye at which they can still be perceived as separate ob- 
jects. From this can readily be calculated the minimum 
visual angle, which, for a normal eye, amounts to 
about i'." (Snellen's test-types have been constructed 
upon the basis of this determination, but for whom this 
work is intended — the veterinarian — it is unnecessary 
to go further into this particular subject or to discuss 
the test-types and their value in the correction of the 
refractive errors in man.) 

Eyes that are defective range from nearly the normal 
visual acuity to mere perception of light. These de- 
fects may be due to errors of refraction or diseases of the 
retina, chorioid, optic nerve, cornea, or lens. A dis- 
turbed nutrition of the eyeball may produce a torpor of 
the retina which causes a reduction in the visual acuity, 
particularly if the illumination is not perfect. In these 
cases the vision is greatly reduced, proportionately 
after dark. 

Accommodation. — Should the power to accommodate 
vision be paralyzed, the image of an object within the 
distance known as infinity — about 20 feet — would be 
very imperfectly formed upon the retina, because the 



THE PRINCIPLES OF VISION 189 

focal point would fall relatively behind the retina. To 
produce acute vision for all near objects it is necessary 
to accommodate the vision, which is done unconsciously. 
For example, take a tripod camera, throw the focusing 
cloth over your head, and focus an object at 100 feet 
distance on the ground glass ; now, without changing the 
focusing apparatus, view some object at, say, 10 feet 
distance from the camera, and you will notice the image 
on the ground glass is blurred. Now rack the lens 
forward, increasing the distance from the lens to the 
ground glass, and the real image will appear sharply 
cut in detail. This is called focusing the object. Ac- 
commodation of vision is practically the same thing, 
except it is done in a different way and by a physiologic 
organ instead of a physical apparatus. Accommodation 
is accomplished not by increasing the distance between 
the lens and the retina, but by increasing the convexity 
of the crystalline lens sufficiently to cause a clearly 
defined retinal image. The ciliary muscle is the governor 
controlling the variations in the convexity of the crystal- 
line lens for all distances within 20 feet. When the 
ciliary muscle contracts, the zonule of Zinn, which 
supports the lens to the muscle, relaxes, allowing the 
lens in its capsule to expand and become more convex 
by its own elasticity. The nearer the object to the eye 
the greater must be the accommodation. 

In young subjects accommodation is very easily ac- 
complished because the lens is soft and very readily re- 



190 OPHTHALMOLOGY FOR VETERINARIANS 

sponds; but in older subjects it loses its elastic qualities 
and responds less readily to the action of the ciliary mus- 
cle, and objects which could formerly be seen near the 
eye have to be carried much farther away to be seen 
distinctly. This is noticeable in man at about forty- 
five years of age, and spheric .lenses have to be placed 
before the eyes to make up the deficiency. The condi- 
tion is known as presbyopia. 

Accommodation is usually determined between two 
points, known as the near point (punctum proximum) 
and the far point (punctum remotum). The near point 
is that point nearest the eye at which a certain object 
can be seen distinctly. The far point is the greatest 
distance from the eye at which the same object can be 
distinctly seen. These points vary with different in- 
dividuals, and especially so when errors of refraction 
exist. 

The hyperopic eye will necessarily have to accommo- 
date proportionately more than normal, and the myopic 
eye less so or not at all. This is because, in the first 
instance, the focus is back of the retina when the ac- 
commodation is at rest; and, in the second instance, it 
is anterior to the retina. In hyperopic eyes the ciliary 
muscle is overdeveloped, while in myopic eyes it is often 
atrophied from non-use. 

During, accommodation the eyes converge propor- 
tionately to the distance, and the pupil is diminished in 
size, Teflexly. The pupil is dilated when the muscle of 



THE PRINCIPLES OF VISION 191 

accommodation is paralyzed. Paralysis of the ac- 
commodation is often caused by contusion of the eye- 
ball, influenza, diabetes, and diseases of the central 
nervous system. Diphtheria is a common cause in man. 
Belladonna and its alkaloids will produce it tem- 
porarily. Spasm of the accommodation often occurs, 
and when an eye is hyperopic it becomes falsely myopic. 
It is partly for this reason that a cycloplegic should be 
used when the eyes are being tested for refractive errors. 
The retina is the receptive coat of the eye (as the dry 
plate receives the image in the camera), and the direct 
image received by the retina falls upon the "macula 
lutea," which is in the direct visual axis. The retina is 
composed of nerve-elements intimately associated with 
the optic nerve-fibers. These nerve-elements, the so- 
called rods and cones — particularly the latter, of which 
the macula is principally composed — are exceedingly 
sensitive to the vibration of light rays. The image is 
produced by the vibration of these light rays refracted 
or focused upon the macula, which is transmitted to the 
optic nerve-fibers, thence to the center of vision in the 
occipital lobes of the brain. If the image falls upon the 
same center of each eye, two images are naturally pro- 
duced, which become one in the visual center, just as 
two pictures are fused into one while looking through 
the spheroprisms of a stereoscope. Double vision (dip- 
lopia) is experienced when one or more of the extrinsic 
muscles are paralyzed. 



192 



OPHTHALMOLOGY FOR VETERINARIANS 



Fields. — When the eyes are fixed upon some object 
directly in front of them, objects at the left are noticed 
by the right half of the retina of each eye, while those at 
the right are noticed by the left half of the retina of each 
eye; those above by the lower half, and those below by 




Fig. 44. — Diagram illustrating the visual path and its relation to the 
visual field, left lateral hemianopsia being shown (Seguin). 

the upper half. These are called the fields of vision, and 
they vary greatly in animals of different kinds. They 
are influenced by the position of the eyeballs, the promi- 
nence of the orbital ridges, the distance between the 
eyes, and the structure of the face. In man, because of 
his requirements, the fields are probably greater than in 



THE PRINCIPLES OF VISION 193 

other animals. The horizontal field is half of a circle, 
180 degrees, while the upper and lower fields are some- 
what less because of the supra-orbital ridges and the 
cheek bones. The inner field of each eye, separately, 
is less because of the nose. 

In the lower vertebrates complete decussation of the 
optic nerves takes place, but in animals of the higher 
order a partial decussation, or crossing over of the inner 
portion of the optic nerves, takes place at the chiasm. 
This causes the image of objects seen from the left field 
to be conveyed to the right visual center, and those from 
the right field to the left visual center. It very often 
happens that an animal cannot see beyond the median 
line, either to the right or to the left. This is known as 
homonymous hemianopia (right and left, respectively). 
Right homonymous hemianopia is due to some defect 
of the optic nerves, tracts, or visual center supplying 
the left half of each retina. Left homonymous hemian- 
opia is due to some defect in the optic nerves, tracts, or 
visual center supplying the right half of each retina. 
When both outer fields are obliterated it is known as 
bitemporal hemianopia, and is due to some defect of the 
inner half of each retina or its optic nerve supply. 
When the inner fields are obliterated (binasal hemianopia) 
the outer half of each retina is involved. 

When hemianopia occurs in both eyes, as it most al- 
ways does, it is due to pressure or disease of the optic 
tracts or visual center. Reaction of the pupil to light, 

13 



194 OPHTHALMOLOGY FOR VETERINARIANS 

when the normal half of the retina is shaded, determines 
the location of the pressure or disease. The pupil fails 
to react to light when pressure is anterior to the so-called 
"reflex arc," that is, anterior to the origin of the third 
nerve. 

The fields of vision are greatly contracted in glaucoma 
and in diseases of the optic nerve and retina, but in a 
work of this nature it is unnecessary to go into such 
details. 

Scotoma. — A portion of the field of an eye may be 
wiped out by reason of disease or atrophy of that portion 
of the retina which should receive it. Such a condition 
is known as a scotoma. For instance, a hemorrhage 
may occur in the macula which will produce a central 
scotoma; that is, the object in the direct visual axis 
cannot be seen, while the other fields are preserved. If 
the macula is normal, but disease and atrophy occur 
in some other portion of the retina, the central field will 
be preserved, but that portion of the field which is 
received by the diseased portion of the retina will be 
obliterated. 



CHAPTER XX 

ERRORS OF REFRACTION 

There is no doubt that some animals have refractive 
errors as well as man, but, as the requirements of vision 
are so vastly different from those of man, it will probably 
be a long time, if ever, when these errors will be corrected 
by the use of lenses. However, it may be well to give the 
veterinary student some knowledge of refractive errors 
at this time. 

There are four principal errors — viz.: Hyperopia 
(farsightedness), myopia (nearsightedness), astigmatism 
(where one meridian is either hyperopic or myopic), and 
presbyopia (the natural failing vision of age). 

Hyperopia is nearly always congenital, and is due to a 
short eyeball from before backward, so that the focus 
falls behind the retina. By some effort of the ciliary 
muscle the focus is brought forward to the retina. In 
some cases, by gradual development, the eye becomes 
normal in its anteroposterior measurements, though in 
many cases hyperopia exists throughout life. A plus 
(convex) spheric lens is necessary to correct this con- 
dition. 

Myopia is just the opposite of hyperopia; that is, the 
eyeball is longer from before backward than normal, 

195 



196 OPHTHALMOLOGY FOR VETERINARIANS 

and the focus of distant objects falls in front of the 
retina; consequently, vision is blurred or imperfect, and 
should the ciliary muscle contract in this case it would 
only increase the myopia. For all near objects, however, 
little or no accommodation is required. Myopia is 
nearly always congenital, though in some cases it is 
acquired. A minus (concave) spheric lens is used to 
correct this error. 

Astigmatism may be simple, compound, or mixed. A 
simple astigmatism is one in which the eye is hyperopic 
or myopic in one meridian only. It is known as regular 
astigmatism when vertical or horizontal and irregular 
when it deviates from these directions. A compound 
astigmatism is one in which the eye is hyperopic or 
myopic combined with an astigmatism of that type. 
Mixed astigmatism is one which is hyperopic in one 
meridian and myopic in the opposite meridian. 

Astigmatism is due to an irregularity in the curva- 
ture or refraction of the cornea, the lens, or both. It 
may be congenital, but is more often acquired. It often 
follows operations or disease of the cornea. Simple 
astigmatism is corrected with a plus or minus cylindric 
lens, as the case may be. Compound astigmatism is cor- 
rected with a plus or minus spheric lens, combined with 
a plus or minus cylindric lens, as the case may be 
compound hyperopic or compound myopic. Mixed 
astigmatism is corrected with a plus spheric and minus 
cylinder or a minus spheric and a plus cylinder. 



ERRORS OF REFRACTION 197 

Presbyopia is a gradual failure of the accommodation 
for near work. Man becomes presbyopic between forty 
and fifty years of age. It is due to a gradual hardening 
of the lens, which fails to respond to the action of the 
ciliary muscle. This error is corrected by placing before 
the eye a plus spheric lens. 

Emmetropia. — An emmetropic eye is one that is 
normal as far as any refractive error is concerned. 
The focus of all distant objects fall upon the retina with- 
out any effort of the ciliary muscle. 

Major-General F. Smith has examined 100 horses' 
eyes, and found that only 1 per cent, were emmetropic, 
3 per cent, were hyperopic, 6 per cent, had mixed 
astigmatism, and 90 per cent, were myopic. 

It is no doubt due to this fact that so many horses shy, 
as distant objects are not clear until they come suddenly 
upon them. Dogs and cats were formerly thought to be 
hyperopic, but recent investigators have found them to 
be myopic. A large number of wild animals' eyes have 
been examined and have been found to be hyperopic. 

Method Used to Determine the Refractive Error. — 
For diagnostic purposes retinoscopy may be used. 
The retinoscope is a small, circular, plane mirror with a 
small hole in the center. A light is placed near the right 
side of the head, shading the eyes, and a reflection of this 
light is thrown, at one meter's distance, into the pupil 
through the refractive media to the retina. The exam- 
iner looks through the central opening, and moves the 



198 OPHTHALMOLOGY FOR VETERINARIANS 

mirror vertically and horizontally. If the reflection cast 
upon the retina moves in the same direction as the 
movement of the mirror, the animal is hyperopic. If 
the reflection moves in the opposite direction from that of 
the mirror, the animal is myopic. If the reflection moves 
with in one meridian and against in the other, mixed 
astigmatism is present. If it moves with in one meridian 
and not at all in the opposite meridian, astigmatism is 
present. If it moves against in one meridian and not 
at all in the opposite meridian, astigmatism is also 
present. In man, the correction is made by placing 
lenses, either plus or minus, before the eye until one is 
found that will neutralize the movement of the reflec- 
tion. When the movement is with, plus lenses are used; 
and when it is against, minus lenses are used. Com- 
pound errors are determined when the movement of the 
same character is greater in one meridian than in the 
opposite meridian. 

In order to get a perfect correction one must control 
the action of the ciliary muscle by the use of a cyclo- 
plegic. Atropin in 1 per cent, solution or homatropin in 
2 per cent, solution may be used. The former may be 
used three times a day for a few days before examina- 
tion, while the latter has its maximum effect in about an 
hour's time. It will be necessary to drop this into the 
eye every ten minutes for an hour at least. The effect 
of this gradually wears away, so that the animal can 
accommodate its vision in twenty-four to forty-eight 



ERRORS OF REFRACTION 199 

hours; while, if atropin is used, the effect will last several 
days. 

To do good work requires a great deal of time, ex- 
perience, and patience. In man, the subjective method of 
examination usually follows retinoscopy, as the patient 
will not always accept his full correction. By the sub- 
jective method is meant placing the patient at a distance 
of 20 feet from the Snellen test-types, and requiring him 
to read the normal line for that distance, either with the 
exact correction by the retinoscope test or by a modifica- 
tion of that correction. 

Of course, it is unnecessary to state that, with the light 
near the head of the animal, it will be necessary to have 
the animal in a darkened room. With much experience 
one can become quite proficient with the use of the 
retinoscope. 



CHAPTER XXI 

MEDICINES USED IN OPHTHALMIC THERAPEUTICS 

There is a great variety of medicines used in the 
treatment of diseases of the eye, but it is better to become 
familiar with the action of a few remedies and to know 
when to use them. 

Antiseptic Washes: 

Normal salt solution is a \ of i per cent, solution of common salt. This 
makes an excellent cleansing agent in mild cases, and is safe to use. 

Boric acid in saturated solution. A feebly antiseptic and safe wash 

to use. 
' Corrosive sublimate in from i : 5000 to 1 : 2000 solutions. This is 
more antiseptic, but also more apt to be followed by reaction when 
strong solutions are used. 

Nitrate of silver in 2 per cent, solution. It is better to apply this 
with a swab of cotton or a camel's hair brush. It . is converted 
into chlorid of silver when it comes in contact with the tears, and 
should be immediately washed off with sterile water. 

Argyrol, one of the albumose of silver salts, used in solutions of from 
10 to 50 per cent. The strong solutions should be used only in 
extreme cases of purulent inflammation. Each manufacturer has 
a name for his special preparation — protargol, argentamin, argonin, 
etc. — which contain different amounts of silver. 

Astringents: 

Sulphate of zinc in \ to ^ of 1 per cent, solution. 

Sulphate of copper. 

Alum. The two last are usually used in the crystal form, rubbed on 

the everted conjunctiva, and immediately washed off. 
Tannate of glycerin, U. S. P. 
200 



MEDICINES USED IN OPHTHALMIC THERAPEUTICS 201 

Local Anesthetics: 

Cocain hydrochloric! in 2 to 10 per cent, solutions. 
Holocain, 1 per cent, solution. 

The first also dilates the pupil. The last is feebly antiseptic and 
does not dilate the pupil. 

Caustics: 

Silver nitrate stick is used to touch ulcerated portions of the lid. It 
is not used on the globe except to stimulate the edges of an open 
wound. 

Tincture of iodin should never be dropped into the eye, but it is valuable 
to apply to sloughing ulcers of the cornea or lids, from the point of 
a pencil of cotton. 

Carbolic acid is used in cases in which the tincture of iodin is indi- 
cated, and in the same way. 

The actual cautery. This may be used in the form of an electric 
cautery, or a fine platinum wire may be heated in an alcohol flame. 
It is used in cases of sloughing ulcer of the cornea and in one about 
to perforate. Great care must be exercised in its use. 

Agents Affecting the Size of the Pupil: 
Mydriatics dilate the pupil. 

Atropin sulphate, 1 per cent, solution. 
Homatropin hydrobromid, 2 per cent, solution. 
Hyoscyamin hydrobromid, 1 per cent, solution. 
Duboisin sulphate, 1 per cent, solution. 
Scopolamin, \ to 1 per cent, solution. 

The first two are the more reliable. They paralyze the accommo- 
dation (cycloplegia) as well as dilate the pupil (mydriasis). 
The first has a more lasting effect, and should be used in cases 
of iritis, injuries, and ulcers of the cornea. The second is used 
more for temporary effect for the examination of the fundus, etc. 
Myotics contract the pupil. 

Pilocarpin hydrochlorid, 1 to 2 per cent. 
Eserin sulphate, \ to 1 per cent, solution. 

Lymphagogues: 

Dionin, 5 to 10 per cent, solutions. 

Redness and edema of the conjunctiva often follow the initial use 
of dionin, which soon subsides. In severe cases of iritis and 
glaucoma the powder is often used in place of the solution. 



202 OPHTHALMOLOGY FOR VETERINARIANS 

Hemostatics: 

The extracts of the suprarenal gland of the sheep. There are numerous 
preparations of this in solution, such as adrenalin chlorid, adrin, 
etc. They are used in operations to lessen hemorrhage. In opera- 
tions on the lids they should be injected hypodermically. 

Ointments: 

Yellow oxid of mercury, i to 2 per cent. 

Red iodid of mercury, \ of 1 per cent. 

Iodoform, 10 to 20 per cent. 

Aristol, 10 to 20 per cent. 

Oxid of zinc, U. S. P. 

Ichthyol, 5 to 20 per cent. 

The first four are used as indicated, in keratitis and ulcer of the 
cornea. The two last are used in diseases of the skin about the 
lids. Equal parts of vaselin and lanolin are used as a base. 

Powders: 
Boric acid. 

Finely powdered iodoform. 
Calomel. 
The first two are often mixed in equal parts and used as a dusting- 
powder following operations on the lids. They are of great value 
in purulent ulcers of the cornea. 

Combinations: 

When two or more of these medicines are indicated, they may be mixed, 
if not incompatible; for instance, atropin or pilocarpin may be 
mixed with an ointment or with a collyrium, etc. It is better to treat 
each case according to its requirements and not have too many 
"set" formulas.- 

More accurate percentage solutions can be made by using the Metric 
System. 



INDEX 



Abrasions of cornea, 166 
Abscess of lid, 42 

treatment of, 42 
Accessory eyelid, 27 
Accidents attending extraction of 

cataract, 149 
Accommodation, 180, 189, 190 

muscle of, 25 

paralysis of, 191 

spasm of, 191 
Acuity of vision, 187 
Albinos, 24 
Amblyopia, toxic, 134 

treatment, 135 
Anatomy of eye, n 
Anemia of retina, 127 
Anesthetics, local, 201 
Aniridia, n 1 
Ankyloblepharon, 38 

operation for, 55, 56 
Antiseptic washes for eye, 200 
Aqueous humor, 21 

turbid, 30 
Artery, hyaloid, 26, 27 
Artificial eye, 172 
Astigmatism, 80, 196 

compound, 196 

mixed, 196 
Astringents, 200 
Atrophy of optic nerve, 135, 175 

of retina, 129, 130 

Blepharitis, 67 
marginalis, 38, 72 



Blepharitis marginalis, treatment 

of, 39 
Blepharospasm, 38, 89 
Blindness, moon, 155 
Bowman's membrane, 20, 30, 88, 97 
Bulbar portion of conjunctiva, 27 
Buphthalmus, 105 
Burns of conjunctiva and cornea, 8^ 

of lid, 35 

Canal of Petit, 26 
Canthoplasty, 54, 99 
Canthotomy, 98 
Capsular cataract, 140, 141 
Capsule of lens, 14, 25, 26 

Tenon's, 12, 61 
Carcinoma of lid, 42 
Caruncle, 27 
Cataract, 31, 137, 157 
capsular, 140, 141 
discission of, 144 
extraction of, 145 

accidents attending, 149 
dressings following, 151, 152 
operations for, 144 
posterior polar, 3, 138 
senile, 139 
traumatic, 138 
Cataracts, classification of, 137 
Catarrhal conjunctivitis, acute, 64 
causes, 65 
diagnosis, 65 
treatment, 66 
Caustics, 201 

203 



204 



INDEX 



Chalazion, 30, 40 

treatment of, 41 
Chamber, anterior, 21, 22 
exudations in, 31, 113 

posterior, 21 
Chambers of eye, 14 
Chemosis, 30 
Choked disk, 134 
Chorea, 38 
Chorioid, 15, 25, 131 

diseases of, 130 

function of, 16 

layers of, 16, 17 

pigment of, 15, 16, 17 
Chorioiditis, 131, 170 

purulent, 132 
Ciliary body, 24 
diseases of, no 
tumors of, 121, 122 

muscle, 25 

processes, 26 

region, wounds of, 115 

vessels, 15 
Coats of eye, 14 
Coloboma of iris, in 
Compound astigmatism, 196 
Concave lenses, 186 
Congenital pupil, in 
Conjugate foci, 183 
Conjunctiva, 15, 27, 30, 33, 34, 75, 
80, 83, 88, 146 

bulbar portion, 27 

burns of, 83 

chemosis of, 30 

diseases of, 64 

foreign bodies in, 80 
treatment, 81 

palpebral, 27, 72, 79 

tuberculosis of, 79 

tumors of, 84-86 

xerosis of, 75 
Conjunctivitis, 64, 86 



Conjunctivitis, acute catarrhal, 64 
causes of, 65 
diagnosis of, 65 
treatment of, 66 
chronic, 66 

treatment of, 68 
follicular, 74 
membranous, 76 
phlyctenular, 71 
purulent, 30, 68 
symptoms of, 68 
treatment of, 69 
Contusions, 162 
Convex lenses, 186 
Cornea, 20, 30, 43, 66, 79-81, 83, 
160 
abrasions of, 166 
burns of, 83 
diseases of, 88 
epithelioma of, 20, 21 
foreign bodies in, 80 

treatment, 81 
herpes of, 99 
layers of, 20 
opacities of, 106 

treatment of, 107 
perforating wounds of, 166 
staphyloma of, 102, 103 
ulcers of, 71, 82, 90-93 
causes, 91 
treatment, 93 
xerosis of, 102 
Corpora nigra, 23 
Cowpox, 42, 71, 91 
Crystalline lens, 25, 31, 67 
capsule of, 14, 25, 26 
construction of, 25 
diseases of, 137 
luxation of, 142 
nucleus of, 26 
opacity of, 31 
shape of, 25 



INDEX 



205 



Cyclitis, 30, 114, 151, 156, 170 

treatment of, 116, 117 
Cylindric lenses, 186 
Cysts of iris, 119 

Dacryocystitis, 57 

Decreased tension, 32 

Dendritic keratitis, 100 

Descemet's membrane, 20, 21 

Desiccation keratitis, 101 

Detachment of retina, 27, 128 

Dilator pupillae muscle, 23 

Diphtheria in fowls, 76, 77 

Diplopia, 80, 191 

Discission of cataract, 144 

Disk, choked, 134 
optic, 14 

Dislocation of crystalline lens, 
142 

Distichiasis, 44 

Dressings after extraction of cat- 
aract, 151, 152 

Duct, meibomian, 30 
stenosis of, 58 

Ecchymosis of lids, 35 
Ectopia pupillae, 111 
Ectropion, 36 

operations for, 46-50 
Edema of lids, 35 

of nictitans membrane, 87 

of retina, 127 
Elephantiasis of lids, 37 
Emphysema of lids, 35 
Enucleation, 118, 170, 171 
Enzootic ophthalmia, 69 
Epiphora, 29, 36, 57 
Episcleral tissue, 15, 27 
Epithelioma of cornea, 20, 21 
Errors of refraction, 195 

methods used to determine, 
197 



Eversion of lids, 36 

Examination, systematic, of eye, 

29 
Exenteration, 175 
Exophthalmus, 91 
Extraction of cataract, 145 
accidents attending, 149 
dressings following, 151, 152 
Eye, anatomy of, n 
. antiseptic washes for, 200 

artificial, 172 

chambers of, 14 

coats of, 14 

foreign bodies in, 168 

haw of, 28 

internal structure of, 14 

systematic examination of, 29 
Eyeball, muscles of, 59 

prolapse of, 172 
Eyelid, 34 

accessory, 27 

third, 12 

tumors of, 41 

Fetal life, pupil in, 24 
Fields of vision, 192 
Filamentous keratitis, 100 
Fluid, vitreous, 27, 32 
Foci, conjugate, 183 
Focus, principal, 182 

virtual, 184 
Follicular conjunctivitis, 74 
Foramen, optic, 14, 61 
Foreign bodies in conjunctiva and 
cornea, 80 
treatment of, 81 
in eye, 168 
Fornix conjunctivae, 34 
Fossa petellaris, 25 
Fovea centralis, 18, 20 
Fracture of orbit, 174 
Fundus, reflex, 17, 24 



206 



INDEX 



Gland of Harder, 28 
Glands, meibomian, 33, 37, 40 

mucous, 34 
Glaucoma, 30, 32, 115, 157-159 
Glioma, 130 
Globe, injuries of, 162 
complications in, 165 
treatment of, 166 
with foreign bodies remaining 
in eye, 168 
lacerations of, 164, 165 
punctures of, 163, 164 
Grafts, Thiersch, 49 
Grape-kernels, 24 

Harder, gland of, 28 
Haw of eye, 28 
Hemianopia, 195 
Hemorrhage in retina, 128 
Herpes of cornea, 99 

zoster, 99 
Hordeolum, 40 
Humor, aqueous, 21 
Hyaloid artery, 26, 27 

membrane, 14, 26 
Hydrophthalmus, 105 
Hyperemia of retina, 128 
Hyperopia, 195 
Hyphemia, 113 
Hypopyon, 89, 92, 93 

Image, virtual, 183 

Increased tension, 32, 158 

Inflammation of nictitans mem- 
brane, 86 
sympathetic, 116 

Influenza, 91 

Injuries of globe, 162 

complications in, 165 
treatment of, 166 
with foreign bodies remaining 
in eye, 168 



Interstitial keratitis, 108, 109 
Inversion of lids, 36 
Iridectomy, 118, 148 
Iridochorioiditis, 131 
Iridocyclitis, 92, 114, 157 
Iridodialysis, 162 
Iridodonesis, 21 
Iris, 21, 22, 25, 31 

colomba of, in 

cysts of, 119 

diseases of, no 

pigment of, 22-24 

prolapse of, 150 

tremulous, 21, 31 

tuberculosis of, 120 

tumors of, 119, 121, 122 
Iritis, 92, 112, 114, 145, 151, 156, 
170 

secondary, 115 

symptoms of, 114 

treatment of, n 6-1 18 

Keratectasia, 105 
Keratitis, 36, 88, 90 

dendritic, 100 

desiccation, 101 

filamentous, 100 

interstitial, 108, 109 

neuroparalytic, 101 

phlyctenular, 71, 99 

symptoms of, 89 
Keratoconus, 105 
Keratoglobus, 105 
Keratomalacia, 102 

Lacerations of globe, 164, 165 
Lacrimal apparatus, diseases of, 57 

sac, 34 
Lagophthalmus, 37, 91 
Lamina cribrosa, 15 
Lashes, 33, 39 

in dog and pig, 33 



INDEX 



207 



Layers of chorioid, 16, 17 
of cornea, 20 
of retina, 18 
Lens, crystalline, 25, 31, 67 
capsule of, 14, 25, 26 
construction of, 25 
diseases of, 137 
luxation of, 142 
nucleus of, 26 
opacity of, 31 
shape of, 25 
Lenses, 186 
concave, 186 
convex, 186 
cylindric, 186 
spheric, 182, 186 
Lenticonus, 145 
Levator palpebrarum, 29, ^3, 
Lids, 39, 71 
abscess of, 42 

treatment, 42 
burns of, 35 
carcinoma of, 42 
diseases of, ^3 
ecchymosis of, 35 
edema of, 35 
elephantiasis of, 37 
emphysema of, 35 
eversion of, 36 
in trichinosis, 30 
inversion of, 36 
operations on, 45 
sarcoma of, 42 
tuberculosis of, 37 
tumors of, 41 
ulcers of, 42 
wounds of, 36 
Ligament, palpebral, ^3 
suspensory, 26 
tarsal, ^3 
Ligamentum pectinatum, 22 
Lupus, 42 



37 



Luxation of crystalline lens, 142 
Lymphagogues, ocular, 201 

Macula lutea, 18 
Meibomian duct, 30 
stenosis of, 58 
glands, S3, 37, 40 
Membrana nictitans, 12, 27, 81 
action of, 28 
edema of, 87 
in tetanus, 87 
inflammation of, 86 
pupillaris, 24 
Membrane, Bowman's, 20, 30, 8, 
97 
Descemet's, 20, 21 
hyaloid, 14, 26 
Membranous conjunctivitis, 76 
Mixed astigmatism, 196 
Moon blindness, 155 
Mucous glands, 34 
Muscle, ciliary, 25 
dilator pupillae, 23 
of accommodation, 25 
retractor, 12, 61 
sphincter pupillse, 23 
Muscles, action of, 61 
affections of, 61 
extrinsic, 14 
intrinsic, 25 
nerve supply of, 61 
oblique, 14, 59, 61 
of eyeball, 59 
recti, 14, 59 
Mydriasis, n 1 
Mydriatics, 201 
Myopia, 195 
Myosis, in 
Myotics, 201 



Nerve, optic, 14 

atrophy of, 135, 175 



208 



INDEX 



Nerve, optic, diseases of, 133 

sheath of, 14, 61 
supply of muscles, 61 
Neuritis, retrobulbar, 134 
Neuroparalytic keratitis, 101 
Neuroretinitis, 133 
Nictitans membrane, 12, 27, 81 

action of, 28 

edema of, 87 

in tetanus, 87 

inflammation of, 86 

Occluded pupil, 114 
Ointments, 202 
Opacities of cornea, 106 
Opacity of crystalline lens, 31 
Ophthalmia, enzootic, 69 

periodic, 155 

recurrent, 116, 155 
symptoms of, 156 
Ophthalmoplegia, 62 
Ophthalmoscope, 20, 124, 125, i6£ 
Optic disk, 14 

foramen, 14, 61 

nerve, 14 

atrophy of, 135, 175 
diseases of, 133 
sheath of, 14, 61 
Ora serrata, 16, 18, 20, 26 
Orbicularis palpebrarum, 29, 33 
Orbit, fracture of, 174 
Ox eye, 105 

Palpebra, levator, 29, 33, 37 
Palpebral conjunctiva, 27, 72, 79 

ligament, 33 
Pannus, 73, 97, 98 
Panophthalmitis, 118, 132 
Papillitis, 133 
Paracentesis, 118 
Paralysis of accommodation, 191 
Parasites of eye, 176, 178 



Parasites of eyelids, 176 
Perforating wounds of cornea, 166 
Periodic ophthalmia, 155 
Petit, canal of, 26 
Phlyctenular conjunctivitis, 71 

keratitis, 71, 99 
Photophobia, 71 
Phthisis bulbi, 163 
Pigment of chorioid, 15-17 

of iris, 22-24 

of retina, 19 

of sclera, 15 
Pinguecula, 78, 79 
Plica semilunaris, 27 
Posterior polar cataract, 138 
Powders, 202 
Presbyopia, 190 
Principles of vision, 181 
Prolapse of eyeball, 172 

of iris, 150 
Pterygium, 79 
Ptosis, 37, 62 

operation for, 56 
Puncta lacrimalia, 29, 34 
Punctum proximum, 190 

remotum, 190 
Punctures of globe, 163, 164 
Pupil, 24,30, 153, 160, 190, 194 

congenital, 111 

in fetal life, 24 

occluded, 114 

size and shape of, in 
Pupillary membrane, persistent, 24, 

in 
Purulent chorioiditis, 132 

conjunctivitis, 30, 68 
symptoms of, 68 
treatment of, 69 

Recti muscles, 14, 59 
Recurrent ophthalmia, 116, 155 
symptoms of, 156 



INDEX 



209 



Refraction, 181 

errors of, 195 
methods used to determine, 
197 
Retina, 17 

and chorioid, diseases of, 124 

anemia of, 127 

atrophy of, 129, 130 

detachment of, 27, 128 

edema of, 127 

examination of, 124-127 

function of, 18 

glioma of, 130 

hemorrhage in, 128 

hyperemia of, 128 

layers of, 18 

pigment of, 19 

rods and cones of, 19 

vessels of, 20 
Retinitis, 128 
Retinoscope, 197, 198 
Retractor muscle, 12, 61 
Retrobulbar neuritis, 134 
Rods and cones of retina, 19 
Roup, 76 

Saemisch operation, 96, 97 
Sarcoma of lid, 42 
Sclera, 14, 167 

pigment of, 15 
Scotoma, 131, 194 
Senile cataract, 139 
Sheath of optic nerve, 14, 61 
Sheep-pox, 71 
Soot-balls, 24 
Space, circumlental, 25 
Spasm of accommodation, 191 
Spheric lenses, 182, 186 
Sphincter pupillse muscle, 23 
Staphyloma of cornea, 102, 103 
Stenosis of meibomian duct, 58 
Sty, 40 

14 



Suspensory ligament, 26 

Symblepharon, 84 

Sympathetic inflammation, 116 

Synechiae, 114 

Systematic examination of eye, 29 

Tapetum lucidum, 17 

Tarsal ligament, 33 

Tarsitis, 37 

Tarsus, 33, 74 

Tenonitis, 30 

Tenon's capsule, 12, 61 

Tension, 32, 114, 158, 159 

decreased, 32 

increased, 32, 158 
Tetanus, 28 

nictitans membrane in, 87 
Therapeutics, ocular, 200 
Thiersch grafts, 49 
Third eyelid, 12 
Tissue, episcleral, 15, 27 
Toxic amblyopia, 134 
treatment of, 135 
Trachoma, 37, 72, 74, 75, 97 
Traumatic cataract, 138 
Tremulous iris, 21, 31 
Trichiasis, 36, 43 

operation for, 53, 54 

treatment of, 43 
Trichinosis, lids in, 30 
Tuberculosis of conjunctiva, 79 

of lids, 37 

of iris, 120 
Tumors of ciliary body, 121, 122 

of conjunctiva, 84-86 

of iris, 119, 121, 122 

of lids, 41 
Turbid aqueous humor, 30 

vitreous, 30, 31 

Ulcers of cornea, 71, 82, 90-93 
causes, 91 



2IO 



INDEX 



Ulcers of cornea, treatment, 93 

of lids, 42 
Uvea, 17, 26 
Uveal tract, 17, 93 

Vessels, retinal, 20 
Virtual focus, 184 

image, 183 
Vision, acuity of, 187 

fields of, 192 

principles of, 181 
Vitreous, 14, 26, 31 



Vitreous, fluid, 27, 32 
turbid, 30, 31 

Washes, antiseptic, for eye, 200 
Wounds of ciliary region, 115 

of lids, 36 

perforating, of cornea, 166 

Xerosis of conjunctiva, 75 
of cornea, 102 

Zinn, zonule of, 26 



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